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/轻量化替代品，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，由于必须改善性能和减少有害排放，冶金行业面临着开发用于燃气轮机的镍和钴基高温合金的新途径的压力。由于金属间化合物固有的脆性，利用金属间化合物诱人的机械性能开发新材料的尝试只取得了微弱的成功。然而，粉末冶金是用来生产涡轮盘的，粉末冶金的细晶性质以及近净成形能力对加力燃烧室和燃烧室衬里是有吸引力的。粉末冶金成形的高温合金还具有更均匀的组织，从而改善低周热机械疲劳。不幸的是，只有有限数量的预合金/中间合金高温合金粉末可供使用，而且有时发现这些粉末颗粒成分不均匀。此外，较差的可压缩性和烧结过程中的残余气孔率一直困扰着新的Ni PM合金的开发和应用。因此，本建议的两个目标是继续研究开发一种类似于IN600的镍-铬-铁基粉末高温合金，使其残余气孔率最小，并改善压缩性能，并通过添加稀土和/或添加Y来改善优化后的镍粉末高温合金的抗氧化性能。

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.