难变形高温合金GH4175铸态组织及均匀化工艺  

As-cast microstructure and homogenization process of difficult-to-deform GH4175 superalloy

作　　者：林莺莺 于秋颖 贺晓勇 东赟鹏 方爽 陈由红 张敏聪 LIN Ying-ying;YU Qiu-ying;HE Xiao-yong;DONG Yun-peng;FANG Shuang;CHEN You-hong;ZHANG Min-cong(Laboratory of Welding and Plastic Forming,Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]中国航发北京航空材料研究院焊接与塑性成形研究所,北京100095

出　　处：《材料热处理学报》2021年第8期54-60,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51404222,51901218)。

摘　　要：采用热力学计算、光学显微镜、扫描电镜和能谱分析等方法对GH4175合金铸锭进行显微组织、析出相和元素偏析情况分析,并研究了均匀化处理过程中合金组织演变和元素再分配的变化规律。结果表明:GH4175合金铸锭枝晶偏析严重,Nb、Mo、Ti元素偏聚于枝晶间,Nb元素的偏析最为严重,主要析出相为γ′相、M_(23)C_(6)、MC、Laves相及针状δ相。合金铸锭在1150℃时出现低熔点相熔化现象,在1200℃时出现枝晶初熔。合金铸锭均匀化应采用低温预处理加高温扩散的两段式,经1140℃×10 h+1190℃×30 h均匀化处理后,合金中的有害低熔点相回溶,枝晶偏析基本消除,是比较合理的均匀化工艺。Microstructure,precipitates and element segregation of GH4175 alloy ingot were studied by means of thermodynamic calculation,optical microscope,scanning electron microscopy and energy dispersive spectrum analysis,and microstructure evolution and the change of element redistribution during homogenization were studied.The results show that the dendrite segregation of the GH4175 alloy ingot is serious,Nb,Mo,Ti elements are segregated between dendrites,Nb element segregation is the most serious,and the main precipitate phases are γ′phase,M_(23)C_(6) carbide,MC carbides,Laves phase and acicular δ phase.The melting of low-melting phases of the GH4175 alloy ingot appears at 1150℃ and the initial melting of dendritic microstructure occurs at 1200℃.Therefore,the homogenization of the alloy ingot should adopt the two-stage process of low-temperature pretreatment and high-temperature diffusion.After homogenization at 1140℃ for 10 h and then at 1190℃ for 30 h,the harmful low melting point phases in the alloy are re-dissolved,and the dendrite segregation is basically eliminated,which is a reasonable homogenization process for the alloy ingot.

关 键 词：GH4175合金 偏析 均匀化 组织 

分 类 号：TG132.3[一般工业技术—材料科学与工程]