新型镍基粉末高温合金微量元素的相研究

Research on Trace Elements-Containing Phases in a New Type Nickel-Based P/M Superalloy

对新型第3代粉末高温合金母合金、等离子体旋转电极法生产(PREP)粉末和热等静压态合金中的微量元素Hf,Zr和Ta的存在相进行了研究。结果表明:母合金中微量元素Hf,Zr和Ta主要以一次MC型碳化物存在,呈块状、条状和蝶状分布于枝晶间;原始粉末中碳化物大致可分为两类:一类为富Ti,Ta和Nb,另一类为含有Ta,Hf和Zr,两类碳化物均含有一定量非碳化物形成元素Co和Ni及弱碳化物形成元素Cr和Mo,以块状、粒状分布于枝晶间或胞晶间。另外,热等静压态分析表明,微量元素Hf,Ta和Zr主要以晶内和晶界MC型碳化物存在,说明微量元素Hf,Zr和Ta以MC型碳化物存在并具有一定遗传性的特点。与原始粉末相比,热等静压态γ′相和碳化物中的Ta量比较少。

The trace elements Hf-,Zr-and Ta-containing phases in the mother alloy,plasma rotating electrode processing（PREP） powders and hot isostatic pressed（HIPed） state of a new third generation nickel-based powder metallurgy（P/M） superalloy were studied.The results show that the trace elements Hf,Zr and Ta mainly exist as MC-type carbides which locate between the dendrites and in the shape of block,strip and butterfly.The carbides in PREP powders can be broadly divided into two groups.One is rich in Ti,Ta and Nb,and the other contains the elements of Ta,Hf and Zr.The two types of carbides both contain a certain amount of non-carbide forming elements Co and Ni,weak carbide forming elements Cr and Mo,and locate between the dendrites or cellulars and in the shape of block and granular.In addition,the analysis of HIPed alloy show that the trace elements Hf,Ta and Zr mainly exist as intragranular and grain boundary MC carbides.All of these indicate that the trace elements Hf,Zr and Ta are in the survival of MC-type carbides and with the genetic characteristic.Carbides and γ＇ phase of HIPed alloy contain less Ta compared with PREP powders.