粉末高温合金原始颗粒边界与MC型碳化物溶解度的关系  

Relationship between prior particle boundary of powder metallurgy superalloy and solubility of MC carbides

作　　者：张梦迪 刘建涛[1,2,3] 张义文 贾建[1,2,3] 邢鹏宇 ZHANG Meng-di;LIU Jian-tao;ZHANG Yi-wen;JIA Jian;XING Peng-yu(Central Iron and Steel Research Institute,High Temperature Material Institute,Beijing 100081,China;Beijing CISRI-Gaona Materials Technology Co Ltd,Beijing 100081,China;Beijing Key Laboratory of Advanced High Temperature Materials,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]钢铁研究总院高温材料研究所,北京100081 [2]北京钢研高纳科技股份有限公司,北京100081 [3]钢铁研究总院高温合金新材料北京市重点试验室,北京100081

出　　处：《材料热处理学报》2021年第5期50-57,共8页Transactions of Materials and Heat Treatment

基　　金：国家科技重大专项(2017-Ⅵ-0008-0078)。

摘　　要：原始颗粒边界(PPB)是在粉末加热固结过程中MC型碳化物在颗粒边界析出造成的,利用扫描电镜(SEM)和电子探针X射线显微分析仪(EPMA)研究了MC型碳化物在镍基高温合金中的溶解度与粉末高温合金中原始颗粒边界(PPB)的关系。结果表明:强碳化物形成元素(Ti、Zr、Hf、Nb、Ta)对应的MC型碳化物在镍与镍基高温合金中的溶解度顺序为:TiC>NbC>TaC>ZrC>HfC,同时温度越高MC型碳化物的溶解度越大;在镍基高温合金中溶解度较大的TiC容易在粉末高温合金的PPB上析出,而溶解度较小的TaC则避免了这种现象。未添加Ta元素的FGH4098合金中原始颗粒边界(PPB)上的MC型碳化物主要为TiC;添加Ta元素的FGH4098合金,制粉过程中会在粉末颗粒内部析出更多的含Ta的MC′型碳化物,在随后的热等静压过程中,这种MC′碳化物转变成为更高稳定性的MC型碳化物(Ta, Ti, Nb)C。(Ta, Ti, Nb)C存在富Ti的核心,Ti和C元素被"固定"在了碳化物中,阻碍了MC型碳化物在PPB上析出。Prior particle boundary(PPB) is caused by the precipitation of MC carbides at the grain boundary during powder heating and consolidation. The relationship between the solubility of MC carbides in nickel-based superalloys and the PPB in powder metallurgy superalloys was investigated by means of scanning electron microscopy(SEM) and electron probe X-ray microscopy analyzer. The results show that the solubility order of MC carbides corresponding to strong carbide forming elements(Ti, Zr, Hf, Nb, Ta) in nickel and nickel-based superalloys is as follows: TiC>NbC>TaC>ZrC>HfC, and the higher the temperature is, the greater the solubility of MC carbides is. TiC with high solubility in the nickel-based superalloys precipitate easily on the PPB of powder metallurgy superalloys, while TaC with low solubility avoid this phenomenon. The MC carbides on the PPB of FGH4098 alloys without Ta elements are mainly TiC. After adding Ta to the FGH4098 alloy, more MC′ carbides containing Ta will be precipitated inside the powder particles during the powdering process, and in the process of subsequent hot isostatic pressing, this MC′ carbides will transform into(Ta, Ti, Nb)C carbides with higher stability. The(Ta, Ti, Nb)C carbides have a Ti-rich core, and the Ti and C elements are "fixed" in the carbides, which hinder the precipitation of MC carbides on the PPB.

关 键 词：粉末高温合金 PPB MC型碳化物 溶解度 

分 类 号：TG132.3[一般工业技术—材料科学与工程]