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Effect of porosity on hardenability of pm steels
Influence of carbide particles and microstructure on creep of PM alloys B.Shaw et al. (Pennsylvania State University, USA.)
Mechanical properties of PM materials were discussed with reference to microstructure, porosity and presence of carbides. Creep tests were carried out on 434L and 304L stainless steels at 677°C and 35MPa to determine steady state creep rates and deformations. The levels found were considered adequate for automotive use but large differences in creep rupture were found. The results were discussed with regard to porosity and Cr carbides in the samples.
Effect of porosity on hardenability of pm steels S.Saritas et al. (Drexel University, USA.)
Effects of pores on thermal response, including hardenability, of sintered materials were discussed. Porosity has two effects, reduction in thermal conductivity and in the amount of material from which heat must be removed. Effects of porosity on hardenability and thermal conductivity were investigated experimentally for PM steels and compared with prediction by finite difference simulations which studied effect of porosity on the Jominy endquench test.
Processing of sinter-hardening steels M.Baran et al. (Hoeganaes Corporation, USA.)
Sinter hardening of steel was discussed in terms of attainment of good properties and close dimensional tolerances. The paper outlined combination of advanced technologies to optimize properties for stringent applications. Warm compaction and selection of sintering parameters to give best processing conditions and applications were considered.
Suitability of PM steels for sinter hardening in respect of cost and performance S.Berb. (Höganäs AB, Höganäs, Sweden.)
Cost reductions in PM processing and maintenance of mechanical properties were reviewed with regard to use of sinter hardening to reduce the cost of heat treatment and to improve properties. A range of steels, suitable for sinter hardening, was described and related to process conditions and applications.
Metallic foams Titanium patts with controlled porosity U. Wagg et al. ( Fraunhofer Inst. Manufacturing/Advanced Mater., Germany.)
Porous metallic materials, including foams with very high porosity, were reviewed with
www.metal-powder.net
regard to properties and applications. Foams can be made by PM methods, including use of hollow spherica[ powders, in a wide range of alloys. Production of foamed Ti-6%A1-4%V and TiAI was discussed.
Effects of heat treatment and titanium aluminide reinforcement on aluminium alloys
Sintering of aluminium flakes for lightweight applications N.S.Myers, R.M.German University, USA.)
(Pennsylvania
The mechanisms by which these pools form and implications for liquid phase sintering of alloys made from elemental powders was discussed.
Stare
Applications for porous A1 were outlined. A n investigation of sintering of AI flakes, made by melt spinning, was described. Liquid phase sintering was used to bond AI flakes together and to sheet A1. The resulting sandwich structures have densities as low as 0.6gm.cm3 and could be used in automotive parts.
Metal foams for improved energy absorption in passenger vehicles D.Claar et al. (Fraunhofer Centre.Delau,are, USA.)
It was noted that efforts had been made to improve crash-worthiness of rail vehicles consequent on increased speeds by incorporation of parts that crush on impact and absorb energy. A n investigation of A1 foams for this was reported. This involved A1 or steel columns filled with the foam. The foam fillings were reported to increase the stability of the parts and prevent localized buckling which then occurs at several locations to absorb more of the deformation energy and make further compression more difficult.
PM aluminium aUoys Composition and deformation parameters on thermal expansion of aluminium-silicon A.V.Sverdlin et al. (Bradley University, USA.)
Effects of %Si and deformation parameters, temperature and amount of deformation, on coefficient of thermal expansion of PM AI-Si alloys, processed by extrusion or rolling, were investigated. Structure/property re[ations were established. Phase distribution was shown to be the main factor controlling determination of thermal expansion coefficient.
Iron and structural development in sintering of aluminium-coppermagnesium alloys J.Drennan et al. (University of Queensland, Australia.)
It was noted that trace elements, deliberately added or accidental, markedly affect processing and properties of sintered alloys. Effects of Fe in AI-Cu-Mg alloys were investigated. Fe is an impurity remaining from original smelting. During sintering Fe segregates to liquid phase pools which promote sintering.
V.Amig6 et al. ( Polytechnic University of Valencia, Spain.)
Effects of mechanical and thermal treatment and volume fraction and type of reinforcement on tensile properties of 6061A1 alloys reinforced with 5% or 10wt% TiA1 or Ti3AI were investigated. Strength increased with amount of aluminide added in both as extruded and T 6 heat-treated conditions. The main factor leading to failure was considered to be the matrix/reinforcement interface. Density of particle cracks was low. For elevated temperature matrix behaviour was predominant.
PLANSEE SEMINAR The following Abstracts are of papers presented at the 15th International Plansee Seminar, which was held in Reutte, Austria, ~n May 2001.
High performance PM materials Net shape PM processing of chromium-base parts for solid oxide fuel cells W.Glatz et al. (Plansee AG., Reutte, Austria )
Solid oxide fuel cells were discussed with reference to use of PM in making components. A range of Cr-base powders was evaluated for net-shape pressing and sintering characteristics. PM was shown to be a viable method of production. It was reported that the electrochemical performance of net-shape PM parts was encouraging.
Effects of phase size and addition of iron on sintering of tungsten-copper powder F.Dore et al. (lnst. National Polytechnique de Grenoble, Grenoble, France.)
Effects of phase size and small additions of Fe on sintering of W-20wt%Cu powder, made by hydrometallurgical methods, H, or mechanically alloyed M, were investigated. H powders has a phase size of 150 to 450nm. The M powder had a range of mm sizes. 0.2wt%Fe was added. Sintering was at 1090°C to 1250°C for three to 80 minutes. Densities of 88% to 98% w e r e attained. Fe enhanced densification.
MPR March 2002
57
Mechanical properties of PM materials were discussed with reference to microstructure, porosity and presence of carbides. Creep tests were carried out on 434L and 304L stainless steels at 677°C and 35MPa to determine steady state creep rates and deformations. The levels found were considered adequate for automotive use but large differences in creep rupture were found. The results were discussed with regard to porosity and Cr carbides in the samples.
Effect of porosity on hardenability of pm steels S.Saritas et al. (Drexel University, USA.)
Effects of pores on thermal response, including hardenability, of sintered materials were discussed. Porosity has two effects, reduction in thermal conductivity and in the amount of material from which heat must be removed. Effects of porosity on hardenability and thermal conductivity were investigated experimentally for PM steels and compared with prediction by finite difference simulations which studied effect of porosity on the Jominy endquench test.
Processing of sinter-hardening steels M.Baran et al. (Hoeganaes Corporation, USA.)
Sinter hardening of steel was discussed in terms of attainment of good properties and close dimensional tolerances. The paper outlined combination of advanced technologies to optimize properties for stringent applications. Warm compaction and selection of sintering parameters to give best processing conditions and applications were considered.
Suitability of PM steels for sinter hardening in respect of cost and performance S.Berb. (Höganäs AB, Höganäs, Sweden.)
Cost reductions in PM processing and maintenance of mechanical properties were reviewed with regard to use of sinter hardening to reduce the cost of heat treatment and to improve properties. A range of steels, suitable for sinter hardening, was described and related to process conditions and applications.
Metallic foams Titanium patts with controlled porosity U. Wagg et al. ( Fraunhofer Inst. Manufacturing/Advanced Mater., Germany.)
Porous metallic materials, including foams with very high porosity, were reviewed with
www.metal-powder.net
regard to properties and applications. Foams can be made by PM methods, including use of hollow spherica[ powders, in a wide range of alloys. Production of foamed Ti-6%A1-4%V and TiAI was discussed.
Effects of heat treatment and titanium aluminide reinforcement on aluminium alloys
Sintering of aluminium flakes for lightweight applications N.S.Myers, R.M.German University, USA.)
(Pennsylvania
The mechanisms by which these pools form and implications for liquid phase sintering of alloys made from elemental powders was discussed.
Stare
Applications for porous A1 were outlined. A n investigation of sintering of AI flakes, made by melt spinning, was described. Liquid phase sintering was used to bond AI flakes together and to sheet A1. The resulting sandwich structures have densities as low as 0.6gm.cm3 and could be used in automotive parts.
Metal foams for improved energy absorption in passenger vehicles D.Claar et al. (Fraunhofer Centre.Delau,are, USA.)
It was noted that efforts had been made to improve crash-worthiness of rail vehicles consequent on increased speeds by incorporation of parts that crush on impact and absorb energy. A n investigation of A1 foams for this was reported. This involved A1 or steel columns filled with the foam. The foam fillings were reported to increase the stability of the parts and prevent localized buckling which then occurs at several locations to absorb more of the deformation energy and make further compression more difficult.
PM aluminium aUoys Composition and deformation parameters on thermal expansion of aluminium-silicon A.V.Sverdlin et al. (Bradley University, USA.)
Effects of %Si and deformation parameters, temperature and amount of deformation, on coefficient of thermal expansion of PM AI-Si alloys, processed by extrusion or rolling, were investigated. Structure/property re[ations were established. Phase distribution was shown to be the main factor controlling determination of thermal expansion coefficient.
Iron and structural development in sintering of aluminium-coppermagnesium alloys J.Drennan et al. (University of Queensland, Australia.)
It was noted that trace elements, deliberately added or accidental, markedly affect processing and properties of sintered alloys. Effects of Fe in AI-Cu-Mg alloys were investigated. Fe is an impurity remaining from original smelting. During sintering Fe segregates to liquid phase pools which promote sintering.
V.Amig6 et al. ( Polytechnic University of Valencia, Spain.)
Effects of mechanical and thermal treatment and volume fraction and type of reinforcement on tensile properties of 6061A1 alloys reinforced with 5% or 10wt% TiA1 or Ti3AI were investigated. Strength increased with amount of aluminide added in both as extruded and T 6 heat-treated conditions. The main factor leading to failure was considered to be the matrix/reinforcement interface. Density of particle cracks was low. For elevated temperature matrix behaviour was predominant.
PLANSEE SEMINAR The following Abstracts are of papers presented at the 15th International Plansee Seminar, which was held in Reutte, Austria, ~n May 2001.
High performance PM materials Net shape PM processing of chromium-base parts for solid oxide fuel cells W.Glatz et al. (Plansee AG., Reutte, Austria )
Solid oxide fuel cells were discussed with reference to use of PM in making components. A range of Cr-base powders was evaluated for net-shape pressing and sintering characteristics. PM was shown to be a viable method of production. It was reported that the electrochemical performance of net-shape PM parts was encouraging.
Effects of phase size and addition of iron on sintering of tungsten-copper powder F.Dore et al. (lnst. National Polytechnique de Grenoble, Grenoble, France.)
Effects of phase size and small additions of Fe on sintering of W-20wt%Cu powder, made by hydrometallurgical methods, H, or mechanically alloyed M, were investigated. H powders has a phase size of 150 to 450nm. The M powder had a range of mm sizes. 0.2wt%Fe was added. Sintering was at 1090°C to 1250°C for three to 80 minutes. Densities of 88% to 98% w e r e attained. Fe enhanced densification.
MPR March 2002
57