| 摘要 |
1,192,945. Superplastic fine grained alloy. INTERNATIONAL NICKEL Ltd. June 9, 1967 [June 30, 1966], No.26777/67. Heading C7A. A wrought nickel-chromium alloy having an ultrafine gamma-alpha microstructure and containing no more than 2% of other phases such as carbide, eta, laves and carbonitride phases, comprises:- Ni 9%- # at least 19% Co up to 10% # at least 19% Cr up to 55% such that at least 2% is not dissolved in the matrix at 980‹ C., but not exceeding the percentage determined by the relationship % Cr = 68À9 - 0À435 (% Ni) Fe 0-55% Ti 0-2À5% Mg 0-0À1% Zr 0-0À1% Ca 0-0À05% B 0-0À015% and optionally, in a total amount of not more than 7%, C 0-0À1% Mo 0-3% # % Mo +%W/2 = 0-3% W 0-1À5%# Al 0À1-5% % Al + % Ti not over 3À5% Nb 0-2À5% #Nb + % 2 Ta /2= 0-2À5% Ta 0-4% # Cu 0-3% Be 0-1% Si 0-0À5% Mn 0-0À5% V 0-0À2% These alloys exhibit superplasticity if the alpha phase is present from 2-70% and the size of the gamma grains is preferably not more than 3 microns. The alloys may be welded using a matching filler wire. To produce the required microstructure the a phase is caused to precipitate in the alloy which has been plastically deformed in the two phase region, during or after recrystallization. The alloy may also be heated in the two phase region to complete the precipitation and recrystallization. Suitable treatments are:- (1) hot working at 1205‹ C. down to 980‹ C. heating to 980‹ C. during 30 minutes and holding for 20 minutes, and (2) solution treating, quenching in water, cold-working 50%, ageing at 595‹ C. for 16 hours and heating to 980‹ C. during 30 minutes and holding for 20 minutes. Certain alloys within the above range are said to be novel. |
