GB951208A - Improvements relating to sintered alloys - Google Patents

Abstract

A sintered creep-resisting alloy is formed by hot working a powder compact, the original compact being formed from a powder mixture of at least two performed alloys each having a face centred cului structure and a base of one or more of Ni, Co and Fe, the lattice parameter of the alloys differing by more than 0.01% and at least 80% of the powder particles being at least 70 microns (200 mesh B.S.S.) in size. The preformed alloy powders should have melting points differing by not more than 150 DEG C. and the preferred alloys have a base of Ni, Cr and Co. In an example the following two preformed alloy powders, particle size 76-150 microns, were mixed in the ratio of 25% alloy A to 75% alloy B and 75% alloy A to 25% alloy B. The mixed powders were sheathed in mild steel under argon, forged at 1150 DEG C., the sheaths were removed and after resheathing extrusion was effected at 1160 DEG C. .Alloy A.%.Alloy B.% .C.0.078.C.0.616 .Cr.18.2.Cr.20.9 .Co.16.6.Co.18.5 .Ti.2.6.Mo.5.56 .Al.1.32.Ti.1.20 .Si.0.90.Al.5.5 .Mn.0.15.Si.0.16 .Pb.0.001.Mn.<0.1 .Zr.0.02.Pb.0.0002 .B.0.005.Zr.<0.01 .Mg.0.005.B.0.005 .Fe.1.18.Mg.0.005 .Cu.0.01.Cu.0.08 .Bi.<0.0002.Fe.0.23 .Sn.0.01.Bi.<0.0002 .Zn.<0.005.Sn.0.01 .Ni.Balance..Zn.0.01 ...Ni.Balance Other preformed alloys which may be used are: 20% Cr, 17% Co, 2.5% Ti, 1.3% Al, 0.08% C, B and Zr in small amounts and the balance Ni; 15% Cr, 20% Co, 5% Mo, 1.2% Ti, 4.6% Al, 0.15% C, B and Zr in small amounts and the balance Ni; 25% Cr, 10% Ni, 7.5% W, 0.5% C and the balance Co.