On the development of Ni powder metallurgy alloys

烧结粉末冶金（PM）合金作为传统产品的高强度/低重量替代品，在航空航天和汽车工业中是一种有吸引力的材料。对于航空航天工业，由于需要提高性能和减少有害排放物，冶金界一直面临开发用于加工燃气涡轮机使用的镍基和钴基超耐热合金的新途径的压力。利用金属间化合物的有吸引力的机械性能来开发新材料的尝试由于其固有的脆性性质而仅获得了轻微的成功。然而，粉末冶金用于生产涡轮机盘，粉末冶金的细晶粒性质沿着近净成形能力对于加力燃烧室和燃烧室衬套应该是有吸引力的。粉末冶金形成的高温合金还可以具有更均匀的微观结构，从而改善低循环热机械疲劳。不幸的是，只有有限数量的预合金/母合金超合金粉末是可用的，并且有时发现这些粉末具有粉末颗粒组成的不均匀性。 此外，烧结时的差的可压缩性和相关的残余孔隙率一直困扰着新型Ni PM合金的开发和应用。因此，本提案的两个目标是继续研究开发具有最小残余孔隙率和改进的可压缩性的类似于IN 600的Ni-Cr-Fe基PM超级合金，以及通过稀土添加物和/或Y添加物来改进优化的Ni PM合金的抗氧化性。

Sintered powder metallurgy (PM) alloys are an attractive material for the aerospace and automotive industries as high strength/low weight substitutes for traditional products. For the aerospace industry pressure has been placed on the metallurgical community to develop new routes for processing Ni and Co-based Superalloys for gas turbine use due to the necessity to improve performance and reduce noxious emissions. Attempts to develop new materials using the attractive mechanical properties of intermetallics have been only marginally successful due to their inherent brittle nature. However PM is used to produce turbine disks and the fine grain nature along with near net shape capability of PM should be attractive for afterburner and combustor liners. PM formed Superalloys can also possess a more uniform microstructure thereby improving low cycle thermo-mechanical fatigue. Unfortunately, only a limited number of prealloyed/master alloy Superalloy powders are available and at times these have been found to suffer from heterogeneity in powder grain composition. As well, poor compressibility and associated residual porosity on sintering have plagued the development of new Ni PM alloys and applications. Thus the two objectives of this proposal are to continue research on development of a Ni-Cr-Fe based PM Superalloy similar to IN600 with minimal residual porosity and improved compressibility and to improve the oxidation resistance of the optimised Ni PM alloy by rare earth additions and/or additions of Y.