It is reported that a Fe-2at%Sm-3%N magnetic alloy had been prepared by implanting N into interstices in Fe-Sm. The material is shown to have good intrinsic magnetic properties and has been fabricated by metal injection moulding. STRUCTURES OF BAPIDLY QUENCHEDIRON-NEODYMIUMBORON-TITANIUMALLOY POWDERS V.A.Glebov et al. Zzv. Russ. Acad. Nauk. Metall., No 1, 1996, 87-94. (In Russian.) It is reported that Fe-14at% Nd-7%B-l%Ti alloy powders had been prepared by centrifugal atomization and droplet quenching onto a cold surface, in Ar. The magnetic properties of the powders were dependent on atomization conditions and heat treatment. The powders were structurally homogeneous.
Hard materials and too/
FATIGUE OF I-LARDMETALS AND CER&lETS H.G.Sockel et al. (University of Erlsngen-Ntirnberg, Erlangen, Germany.) Znt. J. Refractory
Metals Hard Mater.,
Vo115, No 1/3,1997,103-112. Service conditions for cutting tool materials are discussed with respect to properties, particularly fatigue resistance. Investigations of fatigue under a range of conditions, microstructures and fracture surfaces were described. It is deduced that fatigue is mainly in the ductile phases. Various alloys were studied. The work is reported to allow improvements in materials design. CI-IABACTERISTICSOF TBB BINDER PHASE IN CEMENTED CARBIDES T.W.Penrice. (Consultant, Mt. Juliet, Tennessee, USA.) Znt. J. Refractory Metals Hard Mater., Vol 15, No l/3, 1997,113-121. Properties of binders, particularly Co and some Ni, in cemented carbides are examined with the object of improving the understanding of the role of C deficiency. Mechanical and magnetic properties were determined. Solid solution hardening was found in some alloys for all additives except C. A model where WC acts as a hardener was used. W in solution was found to form non-stoichiometric WC which increased hardening. FACTORS AFFECTING REMOVAL OF ORGANIC RESIDUES DURING PRBSINTERING OF CE&lENTED CARBIDES
M.Rafferty et al. (University of the Witwatersrand, Johannesburg, South Africa.) Znt. J. Refractory Metals Hard Mater., Vol 15, No l/3, 1997, 123-131. It is noted that C is lost from WC-Co during presintering, either as CH, due to direct reduction of C by H or as CO, by carbothermic reduction of W oxides. Energetics of these reactions were investigated to ascertain the factors which will minimize carbonaceous residues in compacts. Presintering temperature and time were found as the main factors. PRODUCTION CAPABILITYAND POWDER PROCESSING OF NANO-STRUCTUREDTUNGSTEN CARBIDE-COBALT L.E.McCandlish et al. (Nanodyne Inc, New Jersey, USA.) Znt. J. Refractory Metals Hard Mater., Vol 15, No l/3, 1997,133-136. Industrial scale production of nano-structured WC-Co powders, with WC grains less than 50 nm uniformly distributed in the Co binder, by use of a spray conversion process, was discussed with regard to process and powder parameters, impurities and use of VC and CrsC, as growth inhibitors. 0 contamination during milling was removed by H reduction. COMPOSITION OF TUNGSTEN CARBIDE-IRON-NICKEI&OBALT CEMENTEDCARBIDES et al. (AB Sandvik B.Uhrenius Hardmetals, Stockholm, Sweden.) Znt. J. Refractory Metals Hard Mater., Vol 15, No l/3,1997,139-149. Binders, other than Co, in cemented carbides, were reviewed. It was noted that the good properties of Co bound materials made Co the most commonly used binder. Difficulties in using binders other than Co were discussed. It is reported that recent predictive work has led to solution of these problems. The paper shows how models may be used. Comparison is made between theoretical and experimental work on WC-Co-Fe-Ni.
STRUCTUBE AND PROPERTIES OF TITANIUMBORJDE-STAINLESSSTEEL PRESSUBELESS SINTERED CERMETS R.Watanabe et al. (Tohoku University, Sendai, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 43, No 1, 1996, 128-133. (In Japanese.) Densification of TiB,-(3 to 25)vol% 316L stainless steel cermets was investigated for pressureless sintering in Ar. Structures and properties of the sintered material were determined. Fine
TiB, powder gave the best results. Fe,B was formed in the 5 to 15% stainless steel materials. Highest bend strength was reported to be 1290 MPa at 15% stainless steel. The presence of Fe borides and Ti oxides is attributed to B and 0 in the TiB, powders. PREDICTION OF PROPERTIES OF TUNGSTENCARBIDE-COBALT CARBIDES J.Dusza. (Ustav Materialoveho Vyskumu SAV, Kosice, Czechoslovakia.) Pokroky Praskove Metal., Vol 34, No 3, 1996, 19-25.( In Czech.) Effects of structure parameters on mechanical and fracture properties of WC-Co were investigated. It is reported that equations could be deduced to link structure parameters to properties. DEVELOPMENTOF COMPOSITIONALLYGRADED SINTEREDBARDMATERXALS K.Tsuda et al. (Sumitomo Electric Industries Ltd., Itami City, Japan.) Powder Metall., Vol 39, No 4, 1996, 296-300. It is reported that a compositionally graded material, with a Ti based ceramic outer layer, a tough cemented WC and carbonitride core and a graded interlayer, had been produced. The outer ceramic layer is reported to have a residual compressive stress of 800 MPa. The material is shown to have higher abrasion resistance and fracture toughness than uniform conventional hardmetals. Adhesion between coating and substrate is attributed to the graded interlayer. FORMATION OF ANOMALOUSLARGE TUNGSTEN CARBIDE GRAINS AND THE PHASE K.H.Cho et al. (Korea Tungsten Co Ltd, Korea.) Mater. Sci. Eng. A, Vol 209, No l/2, 1996,296301. The causes of formation of anomalous large WC grains in micrograined WC-Co were studied. Presence of large WC particles in the powders and decomposition of the n phase by carburizing during sintering are considered. Growth morphology, composition and lattice parameters of the n phase are described.
Intermetallic materials EFFECT OF NTOBIUMON OXIDATION RESISTANCE OF PM TITANIUM ALUMINIDE
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