Vol 51, No l/4, 1995, 122-130. A study of the effects of attritor mill rotation speed and balhtank volume ratio on amorphization of Nii50at%Ti, as a functions of time and energy input, is described. It is shown that the greater the power input the thinner the layers in the powder structure become, the smaller the crystallite size and the less the amorphization time. INTEGRATION OF LOCAL AND GLOBAL MODELLING OF MECHANICAL ALLOYING DEVICES D. Maurice, T.H. Courtney. (Michigan Technological University, Houghton, USA) Metall. and Mater. TkansA, Vol 27A, No 7, 1996, 1981-1986. Two devices, used for mechanical alloying, are compared with respect tp process kinetics and properties, scale and structure of the milled powder. The usefulness of a global description of MA in study of interaction between material properties and process parameters is discussed. BEILAVIOUR OF NICKEL-TITANIUM POWDERS DURING MECIIANICAL ALLOYING W.S. Lee et al. (Korea University, Seoul, Korea.) J: Korean Inst. of MetaIs, Vol 34, No 7, 1996, 886-895. (In Korean.) The use of a pulverizer for MA of Ni5OatXTi powders is reported. The method is shown to have high efficiency which reduced milling time. Energy input is evaluated quantitatively and conditions for amorphization expressed in terms of energy. Amorphization was followed by crystallization of NiTi. ANALYSIS OF MECHANICAL ALLOYING IN VIBRATORY MILL BY MODEL SIMULATION Y.H. Park et al. (Tohoku University, Sendai, Japan.) J. KoreanInst. of Metals,Vol34, No 7, 1996, 896-901. (In Korean.) Computer simulation of ball motions during vibratory milling of metal powder was reported. l-, 2- and 3-dimensional models, involving powder compaction related to energy, were used. It was found that ball motion is related to ball:powder ratio. When the amount of powder was reduced the impact frequency increased. The simulated results are correlated with powder characteristics.
precious metals DEVELOPMENT OF METAL BEARING PLASTIC MOULDING MATERIAL K Hoshino et al. (Mitsubishi Materials Corp., Omiya, Japan.) JJapan Sot. Powder and Powder Metallua Vo142, No 8, 1995, 871-8755. (In Japanese.) 38
MPR June 1997
It is reported that a blend of precious metal powder, organic binder and a plasticizer had been prepared. This can be hand-shaped by a range of techniques to make decorative and other artefacts which are then debound and sintered. The properties of some materials are described.
allowed measurement of forces and stresses was used. Analysis of data gave relationships between density, compressibility, intrinsic stresses and friction between powder and die. Effects of %Co and carbide grain size were discussed.
and testing AND WEAR BEIIAVIOUR
SINGLE SINTERED AUTOMOTIVE CONNECTING RODS
OF INJECTION SPEED STEEL
H. Fenglin. PM Technologt Vol 14, No 3, 1996, 214-224. In Chinese. Production of automotive connecting rods is reviewed. Note is taken of efforts to make these by single sintering to optimize weight. Engine tests are reported to demonstrate reliable operation.
J.M. Torralba et al. (Polytectnic University of Madrid, Madrid, Spain.) Mechanical and wear properties and quantitative microscopy of M2 HSS, made by injection moulding, with a polymer binder, and conventional PM were investigated and compared for gas and water atomized powders. Pin-on-disc wear tests were used against AlzOs.
EURO PM’96: stracts are of
The following papers which
presented at the Conference on Advances in Hardmetals Processing which was held in Stockholm, den, in May 1996.
Processing REACTIONS BETWEEN POLYCRYSTALLINE CARBIDE COMPACTS AND LIQUID NICKEL AND COBALT BINDERS L. Chen et al. (Technical University, Vienna, Austria.) Interactions between a range of carbide and matrix phases during liquid phase sinterlng were investigated by immersing fully dense carbide-only compacts in liquid Ni or Co for short periods. The specimens were examined by scanning electron microscopy with energy dispersive analysis. It was reported that the carbides dissolved in the liquid an precipitated on solidification. The matrix carbides were enriched in MO and/or W. Carbide solubility in the matrix increased with increasing (Mo,W):Ti ratio. This was discussed in terms of core/rim structures. METAL CARBIDE-STEEL COMPOSITES P. Nicolae, B.Eugen. (Metallurgical Research Inst., Bucharest, Romania.) Comparative studies of WC-Co, Tic-steel and (WC,TiC,Co) -steel composites were described. Steel matrices, reinforced with up 50~01% TiC or (WC,TiC,Co) were investigated with regard to physicochemical interactions. INVESTIGATION OF DIE PRESSING TUNGSTEN CARBIDE-COBALT
ELECTRONENERGYSTRUCTUREAND CHEMICAL BONDING OF BORON NITRIDE BASED COMPOSITES V. Ilyasov, I. Nikoforov. (Don State Technical University, Rostov-on-Don, Russia.) Electron structures of nonstoichiometric (3BN were calculated to elucidate the properties. Defficiency of N alters the density of electron states distribution. Calculations were carried out for specimens doped with Ni or Al. The changes were correlated with chemical bonding and properties of the compostes. TRANSVERSE RUPTURE STRENGTH FRACTURE TOUGHNESS AND HARDNESS OF TUNGSTEN CARBIDECOBALT J.W. Eason et al. (RTW Inc., Rogers, USA) The widespread use of TRS tests for carbide materials was discussed. It was noted that the understanding of toughness may be anomalous or incorrect. A reexamination of relationships between hardness, Ki, and TRS was described. Experimental data was presented to illustrate differences and dependencies. It was shown that TRS is a function of both hardness and fracture toughness.
Coatings and ultrahard materials DEFECTS IN CHEMICAL VAPOUR DEPOSITED COATINGS ON CEMENTED CARBIDE CUTTING TOOLS
MIXTURES S. Roure et al. (European Centre for Powder
Metallurgy, Grenoble, France.) Die compaction of WC-Co was investigated with regard to variation of %Co and carbide grain size. A press which
T. Akasawa, H. Mikita. (Toho Kinzoku Co. Ltd., Osaka, Japan.) Anomalous grain growth in CVD coatings on cemented carbides was discussed and it was noted that this may cause deterioration in cutting performance. A study of measures to prevent this was described for a range of coating materials