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Demagnetization of porous iron alloy powder under shock compression
Powder production PRODUCTION OF FINE METAL POWDERS BY ULTRASONIC STANDING WAVE ATOMIZATION 0. Andersen et al. (Stiftung Inst. fur Werkstofftechnik, Bremen, Germany). Int. J. Powder Metall., Vol 31, No 4, 1995, 341. 349. Use of ultrasonic standing wave atomization for production of powders less than 15pm is described. Atomization is by action of acoustic forces on the molten metal jet. Cooling rates of 2xlO”degC,sec-’ are deduced. Effects of process parameters are evaluated. Sn, Cu and Mg powders were characterized for size and size distribution.
Pressing DEMAGNETIZATION OF POROUS IRON ALLOY POWDER UNDER SHOCK COMPRESSION H. Oda et al. (Tokyo Inst. of Technology, Tokyo, Japan). Appl. Phys. Z&t., Vol 66, No 3, 1995, 379-381. It is reported that demagnetization of porous green Fe alloy compacts occurred under shock consolidation at pressures exceeding 9 GPa and temperatures above 1025°C. This is attributed to the a-y transformation. The mechanism is considered to be consistent with the low value of residual magnetic flux density in incorrectly processed powder.
Sintering “PDTTfl’PrTDmAhTnPROPERTIES OF PM R LASER BULK
“XI.LUBll.” L. Yulong et al. (Jilin University of Technology, Changchiun, China). PM Technol., Vol 13, No 3, 1995, 192-195. (In Chinese.) It is reported that COz laser sintering had been used to process Cu and Fe base compacts. Laser sintering is shown to improve structures and to increase mechanical properties. STUDY OF SINTERING BY A MULTIFUNCTIONAL DILATOMETER J. Takata, N. Kawai (Kobe Steel Ltd, Takasago, Japan). J. Japan Sot. Powder Powder Metall., Vol 41, No 8, 1994, 1012.
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MPR June 1996
1018. (In Japanese.) A multi-functional dilatometer for the study of sintering is described. Measurements of Fe based compacts, containing lubricant, at high heating/ cooling rates, in a dew point controlled atmosphere are reported. The atmosphere control system is also described.
Aluminium MECHANICAL PROPERTIES OF EXTRUDED RAPIDLY SOLIDIFIED ALUMINIUM-IRON-CERIUM T. Sheppard et al. (Imperial College, London, UK) Int. J. Powder Metall., Vol 31, No 4, 1995, 325-333. It is reported that rapidly solidified Al6.7wt%Fe-5.9%Ce powders had been hot extruded to width:thickness ratios of 5:l and 1:l and mechanical properties of the strip determined at ambient and elevated temperatures. Strips were uni-directionally and cross hot rolled to investigate structures and textures. A more homogeneous structure was found in the 5:l strip textures differing between the two rolling modes. Differences are explained on the basis of the Dillamore-Roberts model. EFFECT OF CHARACTERISTICS OF ALUMINIUM-LITHIUM POWDER ON EXTRUDED MATERIALS H. Junsheng et al. (Guangdong University of Technology, Guangzhou, China). PM Technol., Vol 13, No 3, 1995, 211-215. (In Chinese.) Production and characterization of RS A1-2.5%Li-1.6%Cu-1.2%Mg-0.2%Zr alloy powder are described. The effect of powder properties on properties and structure of extruded alloys were determined. Foil shaped powders are shown to have enhanced mechanical properties. CREEP PROPERTIES OF ALUMINIUM ALLOY REINFORCED WITH SHORT ALUMINA FIBRES K. Hongo et al. (Yamagata University, Yonezawa, Japan). J. Japan Inst. Metals, Vol 59, No 9, 1995, 939-946. (In Japanese.) An investigation of the effects of 11 and 18~01% of short AlaOa iibres on creep and density changes at 300 and 500°C is described. At low stresses tertiary creep dominated without necking of the specimens. Primary and secondary creep
were more pronounced at higher stresses. Tertiary creep is associated with grain boundary cavitation. EXTRUSION OF RAPIDLY SOLIDIFIED ALUMINIUM ALLOY POWDER AND APPLICATIONS K Akechi (Sumitomo Electric Industries Ltd, Itami, Japan). J. Japan, Sot. Powder PowderMetall., Vol41, No 8, 1994,907-911. (In Japanese.) Applications of Al alloys, made from rapidly solidified powders, are discussed with respect to properties and processing by powder extrusion and powder forging. HIGH STRENGTH ALUMINIUM ALLOYS PREPARED THROUGH CRYSTALLIZATION OF AMORPHOUS PHASES A. Inoue et al. (Tohoku University, Sendai, Japan). J. Japan Sot. Powder Powder Metall., Vol 41, No 8, 1994, 912-917. (In Japanese.) An investigation of the mechanical properties of Al-(9 to 15)at%(Ni,Y,Co), prepared by extrusion from high pressure gas atomized powders, is described. Comparison is made with alloys made by processing from ordinary RS powders. It is reported that the method, which allows crystallization of amorphous phases, yields improved mechanical properties. POWDER FORGING OF RAPIDLY SOLIDIFIED ALUMINIUM ALLOY POWDERS M. Otsuki et al. (Mitsubishi Materials Corp, Omiya, Japan). J. Japan Sot. Powder Powder Metall., Vol 41, No 8, 1994, 918. 921. (In Japanese.) Powder forging (PF) of RS Al alloy powders is reported to yield materials with good mechanical properties. An experimental study of A1-Si and Al-Fe alloys is described. The PF Al-Fe is shown to have properties as good as extruded material. Powder forging is considered to give good inter-particle bonding by dispersing surface oxides even at low deformations. CHARACTERISTICS OF PRE-ALLOYED ALUMINIUM-MAGNESIUM-ZIRCONIUM POWDER AND EXTRUDED BAR K. Matsuki et al. (Toyama University, Toyama, Japan). J. Japan Sot. Powder
Pressing DEMAGNETIZATION OF POROUS IRON ALLOY POWDER UNDER SHOCK COMPRESSION H. Oda et al. (Tokyo Inst. of Technology, Tokyo, Japan). Appl. Phys. Z&t., Vol 66, No 3, 1995, 379-381. It is reported that demagnetization of porous green Fe alloy compacts occurred under shock consolidation at pressures exceeding 9 GPa and temperatures above 1025°C. This is attributed to the a-y transformation. The mechanism is considered to be consistent with the low value of residual magnetic flux density in incorrectly processed powder.
Sintering “PDTTfl’PrTDmAhTnPROPERTIES OF PM R LASER BULK
“XI.LUBll.” L. Yulong et al. (Jilin University of Technology, Changchiun, China). PM Technol., Vol 13, No 3, 1995, 192-195. (In Chinese.) It is reported that COz laser sintering had been used to process Cu and Fe base compacts. Laser sintering is shown to improve structures and to increase mechanical properties. STUDY OF SINTERING BY A MULTIFUNCTIONAL DILATOMETER J. Takata, N. Kawai (Kobe Steel Ltd, Takasago, Japan). J. Japan Sot. Powder Powder Metall., Vol 41, No 8, 1994, 1012.
46
MPR June 1996
1018. (In Japanese.) A multi-functional dilatometer for the study of sintering is described. Measurements of Fe based compacts, containing lubricant, at high heating/ cooling rates, in a dew point controlled atmosphere are reported. The atmosphere control system is also described.
Aluminium MECHANICAL PROPERTIES OF EXTRUDED RAPIDLY SOLIDIFIED ALUMINIUM-IRON-CERIUM T. Sheppard et al. (Imperial College, London, UK) Int. J. Powder Metall., Vol 31, No 4, 1995, 325-333. It is reported that rapidly solidified Al6.7wt%Fe-5.9%Ce powders had been hot extruded to width:thickness ratios of 5:l and 1:l and mechanical properties of the strip determined at ambient and elevated temperatures. Strips were uni-directionally and cross hot rolled to investigate structures and textures. A more homogeneous structure was found in the 5:l strip textures differing between the two rolling modes. Differences are explained on the basis of the Dillamore-Roberts model. EFFECT OF CHARACTERISTICS OF ALUMINIUM-LITHIUM POWDER ON EXTRUDED MATERIALS H. Junsheng et al. (Guangdong University of Technology, Guangzhou, China). PM Technol., Vol 13, No 3, 1995, 211-215. (In Chinese.) Production and characterization of RS A1-2.5%Li-1.6%Cu-1.2%Mg-0.2%Zr alloy powder are described. The effect of powder properties on properties and structure of extruded alloys were determined. Foil shaped powders are shown to have enhanced mechanical properties. CREEP PROPERTIES OF ALUMINIUM ALLOY REINFORCED WITH SHORT ALUMINA FIBRES K. Hongo et al. (Yamagata University, Yonezawa, Japan). J. Japan Inst. Metals, Vol 59, No 9, 1995, 939-946. (In Japanese.) An investigation of the effects of 11 and 18~01% of short AlaOa iibres on creep and density changes at 300 and 500°C is described. At low stresses tertiary creep dominated without necking of the specimens. Primary and secondary creep
were more pronounced at higher stresses. Tertiary creep is associated with grain boundary cavitation. EXTRUSION OF RAPIDLY SOLIDIFIED ALUMINIUM ALLOY POWDER AND APPLICATIONS K Akechi (Sumitomo Electric Industries Ltd, Itami, Japan). J. Japan, Sot. Powder PowderMetall., Vol41, No 8, 1994,907-911. (In Japanese.) Applications of Al alloys, made from rapidly solidified powders, are discussed with respect to properties and processing by powder extrusion and powder forging. HIGH STRENGTH ALUMINIUM ALLOYS PREPARED THROUGH CRYSTALLIZATION OF AMORPHOUS PHASES A. Inoue et al. (Tohoku University, Sendai, Japan). J. Japan Sot. Powder Powder Metall., Vol 41, No 8, 1994, 912-917. (In Japanese.) An investigation of the mechanical properties of Al-(9 to 15)at%(Ni,Y,Co), prepared by extrusion from high pressure gas atomized powders, is described. Comparison is made with alloys made by processing from ordinary RS powders. It is reported that the method, which allows crystallization of amorphous phases, yields improved mechanical properties. POWDER FORGING OF RAPIDLY SOLIDIFIED ALUMINIUM ALLOY POWDERS M. Otsuki et al. (Mitsubishi Materials Corp, Omiya, Japan). J. Japan Sot. Powder Powder Metall., Vol 41, No 8, 1994, 918. 921. (In Japanese.) Powder forging (PF) of RS Al alloy powders is reported to yield materials with good mechanical properties. An experimental study of A1-Si and Al-Fe alloys is described. The PF Al-Fe is shown to have properties as good as extruded material. Powder forging is considered to give good inter-particle bonding by dispersing surface oxides even at low deformations. CHARACTERISTICS OF PRE-ALLOYED ALUMINIUM-MAGNESIUM-ZIRCONIUM POWDER AND EXTRUDED BAR K. Matsuki et al. (Toyama University, Toyama, Japan). J. Japan Sot. Powder