Nickel-based single crystal alloy and a method of manufacturing the same

Abstract

The present inventions offer a nickel-based single crystal alloy which has a high strength, is easy in conducting the solution heat treatment, hardly gives a harmful phase and is resistant to corrosion at high temperature. A nickel-based single crystal alloy is offered where the composition consists of 7-15 of Co, 0.1-4 of Cr, 1-4 of Mo, 4-7 of W, 5.5-6.5 of Al, 5-7 of Ta, 4-5.5 of Re, 0-0.5 each of Hf and V, and 0-2 each of Ti and Nb in terms of % by weight and residual part substantially consists of Ni wherein said alloy may contain unavoidable impurities

What is claimed is:  
     
         1 . A nickel-based single crystal alloy, characterized in that, the composition consists of 7-15 of Co, 0.1-4 of Cr, 1-4 of Mo, 4-7 of W, 5.5-6.5 of Al, 5-7 of Ta, 4-5.5 of Re, 0-0.5 each of Rf and V, and 0-2 each of Ti and Nb in terms of % by weight and residual part substantially consists of Ni where said alloy may contain unavoidable impurities.  
     
     
         2 . A nickel-based single crystal alloy according    claim 1    wherein said alloy contains 10-14 of Co, 2-3 of Cr, 1.5-2.5 of Mo, 5-6.5 of W, 5.7-6.3 of Al, 5.5-6.5 of Ta, 4.5-5 of Re and 0.01-0.3 of Hf in terms of % by weight.  
     
     
         3 . A method of manufacturing a nickel-based single crystal alloy mentioned in    claim 1    or    2   , characterized in that, a solution heat treatment is conducted at the temperature range of 1,310-1,350° C. and a aging heat treatment is conducted at the temperature range of 850-1,200° C.  
     
     
         4 . A method of manufacturing a nickel-based single crystal alloy according to    claim 3    wherein the solution heat treatment is conducted within ten hours and the aging heat treatment is conducted within thirty hours.  
     
     
         5 . A method of manufacturing the nickel-based single crystal alloy according to    claim 3    or    4    wherein each of the solution heat treatment and the aging heat treatment is conducted in a single step or by means of temperature changes in two to four steps.  
     
     
         6 . A method of manufacturing the nickel-based single crystal alloy according to any of    claims 3    to    5    wherein a preliminary heat treatment at from 1,290° C. to lower than 1,310° C. for two hours or shorter is conducted prior to the solution heat treatment.