GH2909高温合金Nb元素偏析行为及均匀化规律  

Nb element segregation behavior and homogenization law of GH2909 superalloy

作　　者：戚慧琳 郭续龙 陈琦 周扬 Qi Huilin;Guo Xulong;Chen Qi;Zhou Yang(Department of Special Steel Technology,Chengdu Advanced Metal Materials Industrial Technology Institute,Chengdu Sichuan 610303,China)

机构地区：[1]成都先进金属材料产业技术研究院特钢技术研究所,四川成都610303

出　　处：《金属热处理》2025年第2期212-217,共6页Heat Treatment of Metals

摘　　要：通过JMatPro计算了GH2909合金的理论均匀化工艺,采取1130~1190℃热处理对铸态合金进行均匀化试验验证。利用光学显微镜、扫描电镜、电子探针表征铸态及均匀化后的GH2909合金微观组织、元素偏析和Laves相回溶情况。对均匀化后的GH2909合金进行845℃×4 h空冷处理,观察针状η相的分布情况,评估GH2909合金均匀化效果。结果表明,铸态GH2909合金中存在大量低熔点Laves相,Nb元素偏析最为严重。经过1150℃×7 h或1130℃×10 h均匀化后,GH2909合金中Laves相完全回溶。Laves相回溶后,经过1190℃×35 h均匀化,Nb元素偏析系数降低至1.046,残余偏析系数为0.059。对均匀化后的试样进行845℃×4 h空冷处理后,随着Nb元素逐渐扩散均匀,富Nb的针状η相在晶内、晶界大量析出。结合偏析系数和η相析出情况,1150℃×7 h+1190℃×35 h均匀化可实现GH2909合金的完全均匀化。Theoretical homogenization process of GH2909 alloy was calculated via JMatPro and homogenization experimental verification was conducted for the as-cast alloy at 1130℃to 1190℃.Microstructure,element segregation and dissolution of Laves phase of the as-cast and homogenized GH2909 alloy were characterized by means of metallurgical microscope,scanning electron microscope and electronic probe.After heat treatment at 845℃for 4 h and then air cooling for the homogenized GH2909 alloy,the distribution of needle-likeηphase was observed,in order to evaluate homogenization effect of the GH2909 alloy.The results show that a mass of low melting point Laves phase exists in the as-cast GH2909 alloy and Nb element is the most important segregation element.Laves phase dissolves completely in the GH2909 alloy after 1150℃×7 h or 1130℃×10 h homogenization treatment.After complete Laves phase dissolution,1190℃×35 h homogenization treatment decreases segregation coefficient to 1.046 and residual segregation coefficient to 0.059 of Nb element.After heat treatment at 845℃for 4 h and air cooling for homogenized specimens,Nb-rich needle-likeηphase precipitates along grain boundary and in grain with uniform diffusion of Nb element.Combining segregation coefficient withηphase precipitation behavior,1150℃×7 h+1190℃×35 h homogenization treatment can realize complete homogenization of the GH2909 alloy.

关 键 词：GH2909高温合金 均匀化 LAVES相 NB 元素偏析 

分 类 号：TG156.21[金属学及工艺—热处理]