(AD-D014044; US-Patent-4,787,943; US-Patent-Appl-SN-045970) Avail: US Patent and Trademark Office CSCL 11/6 An aluminum alloy containing about 2 to 6 weight percent titanium, about 3 to 11 weight percent of a rare earth of the Lanthanide Series and up to about 3 weight percent of a least one Group VIII metal, balance aluminum, is disclosed. The alloy is preferably prepared by rapid solidification in powder, particulate or ribbon form, and is subsequently compacted under controlled conditions. N89-26960 Department of the Air Force, Washington, DC. METHOD FOR MAKING AN INTEGRAL TITANIUM ALLOY ARTICLE HAVING AT LEAST TWO DISTINCT MICROSTRUCTURAL REGIONS Patent GRA N89-26961 Department of the Air Force, Washington, DC. This invention relates to the processing of titanium articles fabricated by powder metallurgy to improve the microstructure of such articles. In general terms, powder metallurgy involves production, processing and consolidation of fine particles to produce a solid article. The small, homogeneous powder particles result in a uniform microstructure in the final product. If the final product is made net-shape by application of hot isostatic pressing (HIP), a lack of texture can result, thus giving equal properties in all directions. In accordance with the present invention there is provided a process for improving the microstructure of a blended elemental titanium article made by powder metallurgy which comprises, in combination, the steps of hydrogenating the compacted article at a temperature of about 780 to 1020 C to a hydrogen level of about 0.50 to 1.50 weight percent, cooling the thus-hydrogenated article to room temperature at a controlled rate, heating the thus-cooled, hydrogenated article to a temperature of about 650 to 750 C. and applying a vacuum to dehydrogenate the article, and cooling the thus-hydrogenated article to room temperature at a controlled rate. (AD-A207282; WRDC-TR-89-3027) Avail: NTIS HC A05/MF A01 CSCL 01/3 GRA This report covers the work under Task C of Contract F33615-83-C-3208. An SPF based A-10 nose landing gear door was designed using Supral 220 alloy. The part count for the basic door was reduced to 4 components as compared to 52 for the conventional construction method. The superplastic pan comprising the stiffening structure of the door was assembled to the external skin using the ultrasonic weldbonding process. Test results show that the two doors are approximately equivalent in strength. Economic analysis indicates that the SPF door is less than half the cost of the conventional door for production quantities larger than 100. N89-26963# Engineering. GRA Washington Univ., Seattle. Dept. of Mechanical HRR FIELD IN AN ALUMINUM SEN SPECIMEN (AD-A207578; UWA/DME/TR-89/63) Avail: NTIS HC A03/MF A01 CSCL 11/6 Moire interferometry was used to record simultaneously the vertical and horizontal displacements associated with stable crack growth in single edge notched, 2024-0 aluminum specimens. For a small stable crack growth of 1.5 mm, the vertical displacement showed the dominance of the HRR field but the horizontal displacement deviated from the HRR field at the early stage of loading. GRA N89-26964# Army Lab. Command, Watertown, MA. Material Robert J. Dowding Apr. 1989 23 p (AD-A207647; MTL-TR-89-31) Avail: NTIS HC A03/MF A01 CSCL 11/6 Refinement of the microstructure of tungsten-heavy alloys, specifically 90 W-7 Ni-3 Fe, was achieved through heavy cold working followed by a heat treatment that recrystallized and respheroidized the tungsten grains. Hydrostatic extrusion of the alloy to reductions of area of 83 and 96 percent followed by isothermal annealing gives fine, spherical tungsten grains imbedded within the nickel-iron matrix. The finest grain size achieved was 15 microns for the 96 percent extrusion when subjected to an anneal at 1300 C for 2 hours. The apparent activation energy for the process was found to be 530 kJ/mole. This value indicates that volume diffusion is significant in respheroidizing the grains. GRA N89-26965 Department of the Air Force, Washington, DC. METHOD FOR DEVELOPING ULTRAFINE MICROSTRUCTURES IN TITANIUM ALLOY CASTINGS Patent Daniel Eylon, inventor (to AF), Francis H. Froes, inventor (to AF), and Charles F. Yolton, inventor (to AF) 11 Apr. 1989 5 p Filed 4 Dec. 1987 (AD-D014115; US-Patent-4,820,360; US-Patent-Appl-SN-128839) Avail: US Patent and Trademark Office CSCL 11/6 A method is disclosed for improving the microstructure of cast titanium alloy articles. it is comprised of the following steps: hydrogenating the cast article at a temperature near or above the titanium-hydrogen eutectoid of 815 C (of about 780 to 1020 C) to a hydrogen level of about 0.50 to 1.50 weight percent, cooling the thus-hydrogenated article to room temperature at a controlled rate, heating the thus-cooled, hydrogenated article to a temperature of about 650 to 750 C applying a vacuum to dehydrogenate the article, and cooling the thus-dehydrogenated article at a controlled GRA rate. eutectic-type solidification constituents involving MC-type carbides and a Nb-rich Laves phase occur in these alloys. The gamma/Laves eutectic constituent terminates solidification in these alloys. Nb is the dominant element in the evolution of solidification microstructure with C and Si affecting the amounts of gamma/MC and gamma/Laves constituent observed. Simple solidification models predict reasonably well the amount of eutectic constituent observed. N89-26967# Oak Ridge National Lab., TN. DOE DEGRADATION OF Fe-25Cr, Fe-25Cr-20NI AND Fe-25Cr-6AI ALLOYS IN H2/H2O/H2S ENVIRONMENTS AT 700 C K. Vedula and G. M. Michal (Case Western Reserve Univ., Cleveland, OH.) 1 Mar. 1989 26 p (Contract DE-AC05-84OR-21400) (DE89-011873; ORNL/Sub-86-95900/01) Avail: NTIS HC A03 Fe-25 wt pct Cr, Fe-25 wt pct Cr-20 wt pct Ni and Fe-25 wt pct Cr-6 wt pct Al alloys have been exposed to H sub 2/H sub 2 O/H sub 2 S/Ar gas mixtures at 700 C. The mechanisms of formation and degradation of oxide scales on these alloys have been investigated using electron microscopy and surface analytical techniques. The Fe-25Cr-6Al alloy is attacked the least as a result of the formation of a Al sub 2 O sub 3 layer in the scale, whereas the Fe-25Cr-20Ni alloy is attacked the most, through rapid formation of Fe and Ni sulfides. The Fe-25Cr alloy, forms a Cr sub 2 O sub 3 scale containing CrS sub 1.17 precipitates, and other phases which eventually lead to scale breakdown. DOE N89-26968# California Univ., Berkeley. Lawrence Berkeley Lab. OBSERVATIONS ON THE MECHANISMS OF FATIGUE IN Aug. D. Tribula, D. Grivas, D. R. Frear, and J. W. Morris, Jr. 1988 22 p Presented at the ASME Winter Annual Meeting, Chicago, IL, 28 Nov. 1988 Prepared in cooperation with California Univ., Berkeley (Contract DE-AC03-76SF-00098) (DE89-000553; LBL-25831; CONF-881120-10) Avail: NTIS HC A03/MF A01 Near-eutectic Pb-Sn solders are widely used for joints in electrical devices. These are liable to failure by thermal fatigue during operation of the device. Since the thermal fatigue load is often in shear, the mechanisms of thermal fatigue in shear are of particular interest. Recent research has shown that the thermal fatigue of eutectic solders in shear is preceded by the formation of bands of coarsened material in the eutectic microstructure, which concentrate the deformation and cause the nucleation of fatigue cracks. Such coarsened bands are also observed in isothermal fatigue and unidirectional creep in shear. Since creep experiments are relatively simple to conduct and analyze, these have been used to study the formation and growth of coarsened bands. The mechanism includes three steps: the formation of inhomogeneous shear bands, the onset of recrystallization in the shear band to create a planar region of coarsened material, and the propagation of the coarsened band by progressive recrystallization at its tip. The results are applied to thermal fatigue and some of their DOE implications are discussed. N89-26969# Oak Ridge National Lab., TN. Metals and Ceramics Div. EVALUATION OF MECHANICAL PROPERTIES OF TIN FILMS BY ULTRA-LOW LOAD INDENTATION Michael E. OHern, Robert H. Parrish (Vanderbilt Univ., Nashville, 14 P Presented at the 16th TN.), and Warren C. Oliver 1989 International Conference on Metallurgical Coatings and Equipment Exhibit, San Diego, CA, 17 Apr. 1989 (Contract DE-AC05-84OR-21400) (DE89-009618; CONF-890468-2) Avail: NTIS HC A03/MF A01 The mechanical properties of titanium nitride films of varying composition deposited on stainless steel substrates were studied using an indentation technique with a mechanical properties microprobe which allows measurement of film properties without contribution from the substrate material. A polishing technique was 1988 John R. Weeks, Carl J. Czajkowski, and Paul R. Tichler 25 P Presented at the 14th International Symposium on Effects of Radiation on Materials, Andover, MA, 27 Jun. 1988 (Contract DE-AC02-76CH-00016) (DE89-012636; BNL-42692; CONF-880613-32) Avail: NTIS HC A03/MF A01 The High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory (BNL) is an epithermal, externally moderated (by D20) facility designed to produce neutron beams for research. Type 6061 T-6 aluminum was used for the beam tubes, pressure vessel, fuel cladding, and most other components in the high flux area. The HFBR has operated since 1965. The epithermal, external moderation of the HFBR means that materials irradiated in different areas of the facility receive widely different flux spectra. Thus, specimens from a control rod drive follower tube (CRDF) have received 1.5 x 10(22) n/sq cm (E is greater than 0.1 MeV) and 3.2 x 10(23) n/sq cm thermal fluence, while those from a vertical thimble flow shroud received 1.9 x 10(23) n/sq cm (E is greater than 0.1 MeV) and 1.0 x 10(23) n/sq cm thermal. These numbers correspond to fast to thermal fluence ratios ranging from 0.05 to 1.9. Irradiations are occurring at approximately 333 K. The data indicate that the increase in tensile strength and decrease in ductility result primarily from the thermal fluence, i.e., the transmutation of aluminum to silicon. These effects appear to be saturating at fluences above approximately 1.8 x 10(23) n/sq cm thermal at values of 90,000 psi (6700 Kg/sq mm) and 9 percent, respectively. The specimens receiving the highest fluence ratios appear to have less increase in tensile strength and less decrease in ductility than specimens with a lower fast to thermal fluence ratio and the same thermal fluence, suggesting a possible beneficial effect of the high energy neutrons in preventing formation of silicon crystallites. DOE N89-26971# California Univ., Berkeley. Lawrence Berkeley Lab. CRYOGENIC TENSILE PROPERTIES OF AA 2090 A. J. Sunwoo and J. W. Morris, Jr. Mar. 1989 15 p Presented (Contract DE-AC03-76SF-00098) (DE89-012979; LBL-26651; CONF-8903109-4) Avail: NTIS HC A03/MF A01 The influence of base metal temper and filter metal additions on the cryogenic properties Al-Li 2090 weldments are studied. The results show that as the strength of the base metal increases, strength mismatch increases and the joint efficiency decreases. Inhomogeneous deformation is confined to the fusion zone and the strain localization results in premature failure in the weldment. As the temperature decreases, T3 base metal weldments show better properties than T8 base metal weldments. The influence of filler metal additions on the weldment properties shows that the strength is limited without post-weld aging, but the increase in elongation is significant. At 77 K, a 6 Cu addition to 2090 yields the best UTS and elongation combination of the filler metals DOE studied. Mg addition leads to embrittlement at 77 K. (Contract DE-AC03-76SF-00098) (DE89-012981; LBL-26168; CONF-8903109-5) Avail: NTIS HC A03/MF A01 Since subsequent microstructures and properties depend upon initial decomposition processes, the early developments in a binary Al-Li and quaternary Al-Li-Cu-Mg alloy were observed by high resolution transmission electron microscopy. Interpretation of high resolution images involved appropriate image simulations. The as-quenched microstructure was found to consist of small ordered domains which were unaffected by the presence of Cu and Mg alloying additions, BETA (Al sub 3 Zr) dispersoids and grain boundaries, and are thus interpreted as forming by spinodal decomposition. The ordered domains, approximately 4 nm in diameter, were often observed in antiphase with each other and were separated by regions of disordered matrix. No discrete delta (Al sub 3 Li) particles were observed for natural aging times between 24 hours and 3 weeks. DOE N89-26973# Oak Ridge National Lab., TN. ANALYSIS OF MICROSTRUCTURAL DEVELOPMENT IN M. Rappaz, S. A. David, J. M. Vitek, and L. A. Boatner 1989 (DE89-013537; CONF-8905118-10) Avail: NTIS HC A02/MF A01 A detailed analysis of the dendritic microstructure produced in autogenously welded single crystals Fe-15Ni-15Cr has been performed in order to investigate the relationship between growth crystallography and solidification behavior. From a geometrical analysis relating the dendrite growth velocities to the weld velocity, it has been shown that, at a given point of the melt pool surface, selection of the preferred dendrite trunk growth direction occurs according to a minimum velocity (i.e., minimum undercooling) criterion. Knowing the growth rate of the selected dendrite orientation, the dendrite tip radius and the dendrite trunk spacing have been computed using recent theories of rapid solidification of ternary systems. The predicted dendrite growth orientation and spacing have been successfully compared to experimental observations made on electron beam and laser welds, thus clearly demonstrating the effect of crystallography on the microstructural development during weld pool solidification. N89-26974# Oak Ridge National Lab., TN. THE EFFECT OF AGING AT 343 DEG C ON TYPE 308 STAINLESS STEEL WELDS DOE 1989 D. J. Alexander, K. B. Alexander, and Randy K. Nanstad 5p Presented at the 2nd International Conference on Trends in Welding Research, Gatlinburg, TN, 15 May 1989 (Contract DE-AC05-84OR-21400) (DE89-013545; CONF-8905118-12) Avail: NTIS HC A02/MF A01 Three nominally 25 mm (1 in.) thick shielded metal-arc welds were prepared from 304L base plate with 308 filler material, to obtain three different ferrite levels (4, 8, and 12 pct). Portions of these welds were then aged at 343 C for 3000, 10000, and 20000 hours. Charpy V-notch and tensile specimens were taken from the welds. The tensile results were similar for all the specimens and showed little effect of aging on either the yield or ultimate tensile strengths. The Charpy impact properties of the higher ferrite content materials were significantly degraded by these agings, with larger decreases in the impact energy with increased aging time. The microstructures of the welds were examined by metallography and transmission electron microscopy, and the fracture surfaces were examined by scanning electron microscopy. The changes in the mechanical properties and the fractography are discussed in DOE light of the observed changes in the microstructure. N89-26975# Rockwell International Corp., Golden, CO. Report 28, (1981) Oulu Univ., Finland Studies of the weldability problem of austenitic steels have led to new methods for improving weldability. Majetic and Yeo have patented a method on which the weldable surface is oxidized by annealing, or on it is spread a thin layer of certain oxides. The welding speed increases up to 350 percent due to the oxide layer. The weldability problems also disappear when a method invented by Moisio and Leinonen is used. In this case, small amounts of oxygen, carbon dioxide, or steam are added into the customary TIG shielding gases. A third way to improve the weldability is to sandblast the surface to be welded. If the weldability of steel is poor, it is often advisable to use the methods mentioned. The purpose of this study is to clarify the effects of oxidation, sandblasting, and pickling on penetration. The matter is particularly studied by welding tests performed under laboratory conditions. N89-26976*# DOE National Aeronautics and Space Administration. Marshall Space Flight Center, Huntsville, AL. The need for a fast and reliable method to study stress corrosion in metals has caused increased interest in the Slow Strain Rate Technique (SSRT) during the last few decades. PH13-8MoH950 and H1000 round tensile specimens were studied by this method. Percent reduction-in-area, time-to-failure, elongation at fracture, and fracture energy were used to express the loss in ductility, which has been used to indicate susceptibility to stress corrosion cracking (SCC). Results from a 3.5 percent salt solution (corrosive medium) were compared to those in air (inert medium). A tendency to early failure was found when testing in the vicinity of 1.0 x 10(-6) mm/mm/sec in the 3.5 percent salt solution. PH13-8Mo H1000 was found to be less likely to suffer SCC than PH13-8Mo H950. This program showed that the SSRT is promising for the SCC characterization of metals and results can be obtained in much shorter times (18 hr for PH steels) than those required using conventional techniques. Author N89-26977# National Inst. of Standards and Technology, Boulder, FRACTURE BEHAVIOR OF A PRESSURE VESSEL STEEL IN The reasons for the scatter of fracture toughness in the ductile-to-brittle transition region, as well as the mechanisms leading to cleavage fracture, were investigated for a quenched and tempered pressure vessel steel, DIN 20 MnMoNi 55. The fracture surfaces indicate that cleavage fracture starts at one small area in the ligament, the cleavage initiation site. Cleavage initiation occurs ahead of the crack tip at the location of the maximum normal stresses. Fractography and metallography show four different types of initiation sites. The mechanisms which may trigger cleavage fracture at these initiation sites are discussed. The results indicate that the scatter of fracture toughness is due to the scatter in the distance between the cleavage initiation site and the fatigue crack tip. GRA N89-26978# Oak Ridge National Lab., TN. Engineering Technology Div. RATE-SENSITIVITY AND SHORT TERM RELAXATION BEHAVIOR OF AISI TYPE 304 STAINLESS STEEL AT ROOM TEMPERATURE AND AT 650 C; INFLUENCE OF PRIOR AGING Marina B. Ruggles and Erhard Krempl (Rensselaer Polytechnic Inst., Troy, NY.) 1989 25 p Presented at the Joint ASME/JSME Pressure Vessel and Piping Conference, Honolulu, HI, 23-27 Jul. 1989 (Contract DE-AC05-84OR-21400) (DE89-007823; CONF-890721-9) Avail: NTIS HC A03/MF A01 The strain rate sensitivity and short term relaxation behavior of Type 304 Stainless Steel were investigated in the uniaxial strain rate jump tests with intermittent periods of relaxation at room temperature and at 650 C. At room temperature material exhibited conventional strain rate sensitivity and no strain rate history effect. The high-temperature experimental results revealed a complex and dramatically different material behavior. At 650 C the pattern of strain rate sensitivity was not set as soon as the plastic flow was fully established, but continued to evolve with the further straining in the plastic range. Test results indicate that at 650 C the material may exhibit a strain rate history effect. Both at room temperature and at 650 C the relaxation behavior was independent of the stress and/or strain level at the beginning of the relaxation, but depended nonlinearly on the strain rate preceding the relaxation test. Prior aging had no significant influence on the rate-dependent material response. The irregular material behavior at 650 C is attributed to dynamic strain aging as indicated by serrated stress-strain curves (the Portevin-LeChatelier effect). DOE N89-26979# Oak Ridge National Lab., TN. Metals and Ceramics Div. LOSS OF GRAIN BOUNDARY SEGREGANT DURING ION MILLING 1989 E. A. Kenik 7 p Presented at the Microbeam Analysis Society Meeting, Asheville, NC, 16 Jul. 1989 (Contract DE-AC05-84OR-21400) (DE89-007835; CONF-890748-3) Avail: NTIS HC A02/MF A01 Bismuth segregates to grain boundaries in copper at intermediate temperatures (400 to 800 C). Currently, X-ray microanalysis is being used to measure the degree of equilibrium segregation as a function of boundary character. As part of that study, transmission electron microscopy specimens were prepared by several techniques in order to select that method which specimens. optimum Electropolishing produced produced specimens of marginal quality because of preferential grain boundary attack. On the other hand, ion-milling produced good, thin specimens with little or no boundary attack. However, X-ray microanalysis on specimens ion-milled at room temperature whereas analysis on indicated no bismuth segregation, electropolished specimens indicated bismuth segregation. A loss of bismuth from the ion-milled specimens was proposed to result from the high vapor pressure of bismuth at slightly elevated temperatures. The use of a liquid nitrogen cold stage during ion-milling minimizes the loss of bismuth. It is likely that beam heating during ion-milling is a contributing factor in this process and must be controlled. DOE assessment of the structural integrity of the vessel. Experimental results from tests on large clad and unclad plate specimens with surface flaws have shown that: (1) a tough surface layer composed of cladding and/or a heat-affected zone has arrested running flaws in clad plates under conditions where unclad plates have ruptured, and (2) the residual load-bearing capacity of clad plates with large subclad flaws significantly exceeded that of an unclad plate. The fracture surfaces of unclad plates suggest that the flaw evolves through alternately tunneling then breaking to the surface. In the case of clad plates, it is hypothesized that the tough, strong surface layer inhibits the tunneled flaw from propagating to the surface. DOE N89-26981# Sandia National Labs., Albuquerque, NM. QUANTITATIVE THIN FILM X-RAY MICROANALYSIS OF Nb MODIFIED TIзAI A. D. Romig, Jr., T. J. Headley, M. J. Carr, and M. J. Cieslak 1989 9 p Presented at the Microbeam Analysis Society Meeting, Asheville, NC, 16 Jul. 1989 (Contract DE-AC04-76DP-00789) (DE89-009946; SAND-89-0683C; CONF-890748-7) Avail: NTIS HC A02/MF A01 Advanced titanium-aluminum intermetallic alloys (often simply called titanium aluminides) have certain properties which make them potentially attractive as advanced aerospace alloys. In order to utilize these alloys in engineering applications, it is necessary to process the alloys in a variety of ways including casting, hot forming and welding. All of these processes modify the microstructure of the alloy, which in turn directly influences the properties. The key to optimizing the alloy's properties is to control the microstructure by careful control of the processing parameters. Control for the microstructure requires a thorough understanding of the evolution of the microstructure, including elemental partitioning between the various phases which form in the alloy. Analytical electron microscopy (AEM) is an ideal way to characterize the microstructures on a fine spatial scale. Such high spatial resolution microanalysis is required to understand the microstructural evolution in these alloys. In this case, the alloy is a Nb modified Ti sub 3 Al, and the partitioning behavior of interest is between a variety of ternary phases which are produced as a function of alloy cooling rate from a single homogeneous high temperature beta phase. The Nb is added to the alloy to enhance its performance, primarily through an improvement in ductility. In this work, the details of the procedure for quantitative analysis of these alloys are presented. Div. DOE N89-26982# Oak Ridge National Lab., TN. Metals and Ceramics RELAXATION RESPONSE OF A533B STEEL FROM 25 TO 600 C R. W. Swindeman and E. Bolling 1989 8 p Presented at the Joint ASME/JSME Pressure Vessel and Piping Conference, Honolulu, HI, 23-27 Jul. 1989 (Contract DE-AC05-84OR-21400) (DE89-010179; CONF-890721-22) Avail: NTIS HC A02 Relaxation tests were performed on A533B steel over the range 25 to 600 C in order to examine the general features of time-dependent deformation. It was found that the relaxation strength increased with the flow stress at low temperatures and was relatively independent of history at high temperatures. In the temperature range 400 to 600 C the inelastic strain rates calculated from the relaxation rates followed stress dependencies that were consistent with expectations based on a model proposed by Hart and coworkers for matrix deformation. DOE (DE89-011181; LA-UR-89-1241; CONF-890772-1) Avail: NTIS HC A02/MF A01 A fundamental property of cubic metals is that slip occurs on close-packed planes in close-packed directions, which for the f.c.c. case results in 12 set of (111) planes/group of zone axes (100) slip systems. This crystallographic restriction on the plastic behavior causes significant crystallographic preferred orientation (texture), hence anisotropy, to develop once a large strain has been imposed. Moreover, whereas annealing can generally reset the flow stress and ductility, it does not generally randomize the texture: therefore most metallic materials have some degree of texture and consequent anisotropy. The problem of earing in deep drawing can be simply related to the variation of r-value with angle from the rolling direction, i.e., the in-plane anisotropy of the sheet. The r-value can be calculated from a given texture with the use of a polycrystal plasticity model. The Los Alamos polycrystal plasticity (LApp) code is based on the Bishop-Hill single crystal yield surface (SCYS) but with a mildly strain-rate sensitive modification where the stress exponent is of order 30. This modification of the SCYS removes the ambiguity of slip system selection inherent in the Bishop-Hill formulation and permits other phenomena to be treated such as latent hardening and pencil glide. N89-26984# California Univ., Berkeley. HISTORY OF THE APPLICATION OF THE GENERALIZED LEWIS ACID-BASE THEORY TO METALS DOE L. Brewer Nov. 1988 6 p Presented at the World Material Congress, Chicago, IL, 24 Sep. 1988 Prepared in cooperation with California Univ., Be rkeley. Lawrence Berkeley Lab. (Contract DE-AC03-76SF-00098) (DE89-012992; LBL-26942; CONF-8809360-1) Avail: NTIS HC A02/MF A01 The history of experiences with intermetallics has been found useful by students seeking my advice on which directions in science they should be emphasizing. In response to their question, I point to a mobile in my office consisting of seven hands pointing in different directions. Science comes up with so many unexpected developments that one's education should have a broad enough base to allow one to branch out in any direction to take advantage of unexpected opportunities. My historical presentation will be a personal account that I hope will serve as a guide to students. There have been many unexpected abrupt changes in my research. DOE A series of Cr films were deposited by physical vapor deposition and ion-assisted deposition as a function of the incident ion energy and the ion/atom arrival-rate ratio, R. Cross section transmission electron microscopy was used to study the microstructure of the substrate/film interface and film surface regions of these Cr films. High-energy ion bombardment (greater than 300 eV) was found to enhance the adhesion of the deposited film owing to the formation of an intermixing layer at the interface region. Hardness data suggest that high ion energy and low ion/atom arrival-rate ratios produce films with relatively high hardness because few pores and many defects are present. DOE Since previous Progress Reports presented results obtained in several other areas of our research, we highlight some results here of our investigations of the energetics of alloy phase diagrams. These have been carried out along both a theoretical and computational front. The theoretical studies were necessitated by the need to apply Green function methods, or the Korringa-Kohn-Rostoker (KKR) formalism, to a diverse number of cases such as isolated impurities, substitutional or interstitial, in pure elemental solids and in substitutionally disordered alloys, and to the treatment of lattice relaxation around impurities. Our computational endeavors were directed toward developing computer programs based on theoretical advances and toward refining existing codes. In the following we describe briefly the results we have obtained thus far along theoretical and computational lines. DOE AN AUGER SPUTTER PROFILING STUDY OF NITROGEN AND OXYGEN ION IMPLANTATION IN TWO TITANIUM ALLOYS B. D. Barton, L. E. Pope, and T. N. Wittberg (Dayton Univ., OH.) 1989 33 P Presented at the 11th Symposium on Applied Surface Analysis, Cleveland, OH, 31 May 1989 (Contract DE-AC04-88DP-43495) (DE89-014734; MLM-3951(OP); CONF-8905167-1) Avail: NTIS HC A03/MF A01 Samples of two titanium alloys, Ti-6Al-4V and Ti-15V3Cr-3Sn-3Al, were ion implanted with a combination of nitrogen (N+) and oxygen (O+). For each alloy, implantation parameters were chosen to give implanted nitrogen concentrations of approximately 10 or 50 atomic percent, from a depth of 100 nanometers to a depth of 400 nanometers. In all but one case, dual energy (200 keV and 90 keV) implantations of nitrogen were used to give a relatively uniform nitrogen concentration to a depth of 300 nanometers. In each case, oxygen was implanted at 35 keV, following the nitrogen implantation, to give an oxygen-enriched region near the surface. The implanted samples were then examined by Auger electron spectroscopy (AES) combined with argon ion sputtering. In order to determine the stoichiometry of the nitrogen implanted regions, it was necessary to determine the N(KVV) contribution to the overlapping N(KVV) and Ti(LMM) Auger transitions. It was also necessary to correct for the ion-bombardment-induced compositional changes which have been described in an earlier study titanium nitride thin films. The corrected Auger electron spectroscopy (AES) depth profiles were in good agreement with theoretical predictions. N89-26988# DOE Pittsburgh Univ., PA. Dept. of Materials Science and Engineering. Gil M. Kim and Gerald H. Meier 31 Jan. 1989 81 p Prepared for ORNL, TN (Contract DE-AC05-84OR-21400) (DE89-014789; ORNL/Sub-83-43346/02-Vol-1) Avail: NTIS HC A05/MF A01 The breakdown mechanisms of preformed oxide scales, Cr203, A1203 and SiO2, have been studied at low oxygen and high sulfur potentials in the temperature range 550 C to 950 C. For Cr203 on Ni-30Cr, sulfur penetration occurs through thin areas in the Cr203 scale. The first sulfides to form on Fe-25Cr and Co-30Cr were observed at the scale/gas interface as the result of Fe or |