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Design of Fe-based wear resistant materials by advanced PM
Literature and crack propagation rates are improved. The crack initiation threshold was unchanged. The results are related to critical defect size, granulometry of the powder and porosity of the compacts.
DESIGN OF Fe-BASED WEAR RESISTANT MATERIALS BY ADVANCED PM
Additions of SiC or A1203 were made to m a c h i n e d Mg a l l o y p o w d e r AZ91 ( M g - 9 . 5 % A I - 1%Zn-0.3 %Mn-0.3 %Si0.2%Cu) which was fabricated by PM. Structure and properties were measured. Distribution of strengthening phases was determined microscopically. Increases in hardness and strength, and reduction in elongation were found. PROPERTIES OF PM Mg ALLOYS
E Y Gutmanas, (Technion, Haifa, Israel). Vol 2, Paper 66, 359-363. Various Fe-based alloys containing additions of Cr, V, Nb and WC and Cr and Nb nltrides were prepared. The final stages of processing were cold sintering at 3GPa, to give full density, and then heat treatment was given to permit diffusion alloying. Hardness, TRS, and volume loss in abrasive wear tests were measured for cold sintered and heat treated specimens. Microstructure was characterized by SEM. Materials of increased wear resistance were produced.
SURFACE CHARACTERIZATION OF PM MARTENSITIC STEEL L Nyborg, et al, (Chalmers University of Technology, Goteborg, Sweden). Vol 2, Paper 67, 364-369. Reaction products of atomization, HIP and creep testing of a martensitic stainless steel were characterized by ESCA and Auger spectroscopy. It was shown that gas atomized particles were coated with a layer ofFe, Cr and Mn oxides averaging 9 nm in thickness. Particles smaller than 30 Ixm were also coated with a S-rich layer less than 1 nm thick. Creep tested specimens were found to fracture at prior particle boundaries (PPB). Fracture was found to be associated with S in the case of HIPed and with S and P on the surface of creep tested specimens. It is suggested that S and P at PPBs contribute to the initiation of creep rupture.
K U Kainer, (Technical University of Clausthal, Clausthal, Germany). Vol 1, Paper 41,519-525. Mg alloys AZ91, MSR and ZE63 were converted to powder by inert gas atomization and mechanical comminution. Powders were characterized and properties related to p r o d u c t i o n parameters. Powders were consolidated by extrusion. Properties of the PM product were compared with those of conventionally produced materials.
J Schroder, et al, (Technical University of Clausthal, Clausthal, Germany). Vol 1, Paper 17, 304-309.
788
IMPROVEMENTS IN PM Ni-BASE SUPERALLOYS I Tomizuka, et al, (National Research Institute for Metals, Tokyo, Japan). Vol 1, Paper 21, 337-345. An alloy design procedure was introduced to obtain a tough, strong, high temperature Ni-base alloy by superplastic forging of HIP-consolidated alloy powder. The procedure is based on the premise that alloy properties are determined by five composition/structure and processing parameters. Relationships between these parameters and the properties were established by experiment and semi-empirical regression analysis.
Tungsten Molybdenum MANUFACTURE OF Ni-CLAD Mo SHEET Y M Korolev, et al, (Refractory and Hard Metals Research Institute, Moscow, USSR). Vol 2, Paper 19, 97-99. Plasma spraying, followed by rolling, was used to coat sintered and rolled Mo sheet with Ni. Optimum process conditions give 5-10% porosity in the coating. To give a bond strength of 50MPa between the coating and substrate the coating thickness must not be less than 0.4mm and the first rolling pass must be 10-15% at 1200°C.
REACTIVE SINTERING OF Ni-BASE CORROSION AND WATER RESISTANT ALLOYS PARTICLE REINFORCED PM Mg ALLOYS
Ni-Si-Mo-Cu alloy and CrB were reactively sintered. Alloys with greatly increased wear resistance and unchanged corrosion resistance, compared with HastelloyC were produced.
N Morishita, et al, (Kobe Steel Ltd, Kobe, Japan). Vol 1, Paper 20, 332-336. A c o r r o s i o n and wear r e s i s t a n t alloy (Ni- 17.5 %Cr-24.0%Mo-3.6%B-2.9%Si1.0%Cu) was produced by HIPing. Powders of
EFFECTS OF SINTERING AND POST-SINTERING HEAT TREATMENT ON MECHANICAL PROPERTIES OF W-Ni-Fe HEAVY ALLOYS T Kohno, O Mayama, (Mitsubishi Metal Corporation, Niigata, Japan). Vol 1, Paper 19, 324-331. Mechanical properties, especially elongation, of specimens not presintered are poor, as are specimens sintered in moist H2. Properties are improved by post sinter heat treatment, at 1150°C for 1 hour in Ar, followed by water quench.
ION BEAM TREATMENT OF CERAMIC POWDERS M Hueberger, et al, (Max-Planck Institute, Stuttgart, Germany). Vol 1, Paper 35,457-467. Ceramic powders B4C, TiC and WC have been subjected to ion implantation with Ar, A1 and Si for the purpose of sinter activation. Untreated and implanted powders were characterized and sinterability compared.
MPR November 1990
DESIGN OF Fe-BASED WEAR RESISTANT MATERIALS BY ADVANCED PM
Additions of SiC or A1203 were made to m a c h i n e d Mg a l l o y p o w d e r AZ91 ( M g - 9 . 5 % A I - 1%Zn-0.3 %Mn-0.3 %Si0.2%Cu) which was fabricated by PM. Structure and properties were measured. Distribution of strengthening phases was determined microscopically. Increases in hardness and strength, and reduction in elongation were found. PROPERTIES OF PM Mg ALLOYS
E Y Gutmanas, (Technion, Haifa, Israel). Vol 2, Paper 66, 359-363. Various Fe-based alloys containing additions of Cr, V, Nb and WC and Cr and Nb nltrides were prepared. The final stages of processing were cold sintering at 3GPa, to give full density, and then heat treatment was given to permit diffusion alloying. Hardness, TRS, and volume loss in abrasive wear tests were measured for cold sintered and heat treated specimens. Microstructure was characterized by SEM. Materials of increased wear resistance were produced.
SURFACE CHARACTERIZATION OF PM MARTENSITIC STEEL L Nyborg, et al, (Chalmers University of Technology, Goteborg, Sweden). Vol 2, Paper 67, 364-369. Reaction products of atomization, HIP and creep testing of a martensitic stainless steel were characterized by ESCA and Auger spectroscopy. It was shown that gas atomized particles were coated with a layer ofFe, Cr and Mn oxides averaging 9 nm in thickness. Particles smaller than 30 Ixm were also coated with a S-rich layer less than 1 nm thick. Creep tested specimens were found to fracture at prior particle boundaries (PPB). Fracture was found to be associated with S in the case of HIPed and with S and P on the surface of creep tested specimens. It is suggested that S and P at PPBs contribute to the initiation of creep rupture.
K U Kainer, (Technical University of Clausthal, Clausthal, Germany). Vol 1, Paper 41,519-525. Mg alloys AZ91, MSR and ZE63 were converted to powder by inert gas atomization and mechanical comminution. Powders were characterized and properties related to p r o d u c t i o n parameters. Powders were consolidated by extrusion. Properties of the PM product were compared with those of conventionally produced materials.
J Schroder, et al, (Technical University of Clausthal, Clausthal, Germany). Vol 1, Paper 17, 304-309.
788
IMPROVEMENTS IN PM Ni-BASE SUPERALLOYS I Tomizuka, et al, (National Research Institute for Metals, Tokyo, Japan). Vol 1, Paper 21, 337-345. An alloy design procedure was introduced to obtain a tough, strong, high temperature Ni-base alloy by superplastic forging of HIP-consolidated alloy powder. The procedure is based on the premise that alloy properties are determined by five composition/structure and processing parameters. Relationships between these parameters and the properties were established by experiment and semi-empirical regression analysis.
Tungsten Molybdenum MANUFACTURE OF Ni-CLAD Mo SHEET Y M Korolev, et al, (Refractory and Hard Metals Research Institute, Moscow, USSR). Vol 2, Paper 19, 97-99. Plasma spraying, followed by rolling, was used to coat sintered and rolled Mo sheet with Ni. Optimum process conditions give 5-10% porosity in the coating. To give a bond strength of 50MPa between the coating and substrate the coating thickness must not be less than 0.4mm and the first rolling pass must be 10-15% at 1200°C.
REACTIVE SINTERING OF Ni-BASE CORROSION AND WATER RESISTANT ALLOYS PARTICLE REINFORCED PM Mg ALLOYS
Ni-Si-Mo-Cu alloy and CrB were reactively sintered. Alloys with greatly increased wear resistance and unchanged corrosion resistance, compared with HastelloyC were produced.
N Morishita, et al, (Kobe Steel Ltd, Kobe, Japan). Vol 1, Paper 20, 332-336. A c o r r o s i o n and wear r e s i s t a n t alloy (Ni- 17.5 %Cr-24.0%Mo-3.6%B-2.9%Si1.0%Cu) was produced by HIPing. Powders of
EFFECTS OF SINTERING AND POST-SINTERING HEAT TREATMENT ON MECHANICAL PROPERTIES OF W-Ni-Fe HEAVY ALLOYS T Kohno, O Mayama, (Mitsubishi Metal Corporation, Niigata, Japan). Vol 1, Paper 19, 324-331. Mechanical properties, especially elongation, of specimens not presintered are poor, as are specimens sintered in moist H2. Properties are improved by post sinter heat treatment, at 1150°C for 1 hour in Ar, followed by water quench.
ION BEAM TREATMENT OF CERAMIC POWDERS M Hueberger, et al, (Max-Planck Institute, Stuttgart, Germany). Vol 1, Paper 35,457-467. Ceramic powders B4C, TiC and WC have been subjected to ion implantation with Ar, A1 and Si for the purpose of sinter activation. Untreated and implanted powders were characterized and sinterability compared.
MPR November 1990