Alloy Design for Nickel-Base Superalloys

An alloy design system has been established for γ′ precipitation hardening nickel-base superalloys.As the first part of our system, a calculation of component phases and predictions of properties of alloys were made possible with help of a regression analysis applied for the reported data.Then approximately 100 alloys were designed through the system and evaluated by creep rupture tests, a tensile test, and a hot corrosion test. A number of alloys developed have creep rupture strength superior to that of commercial alloys(IN-738LC, B-1900Hf, Mar-M247, etc.) when comparison was made among those with a comparable hot corrosion resistance. Some of them showed good tensile properties as well.Afterwards regression analyses were again applied over all the above properties of the alloys we designed and tested. It was found that the properties were well related to structural factors such as alloy composition, γ′ fraction, and γ′ composition. The resultant equations of analyses have been adopted to our alloy design to manufacture superior alloys.