第24卷第6期 2016年12月
材料科学与工艺
MATERIALS SCIENCE & TECHNOLOGY
doi:10.11951/j.issn.1005-0299.20160603
Vol. 24No. 6 Dec.2016
铸锭GH3625合金微观偏析及均匀化热处理
丁雨田，李海峰，王伟，刘建军，郭廷彪，胡勇
（省部共建有色金属先进加工与再利用国家重点实验室（兰州理工大学），兰州730050）
摘要：为消除铸态GH3625合金的显微偏析，改善其热加工性能，建立其均匀化动力学并制订均匀化处理制度，采用Image ProPlus软件、扫描电镜(SEM)和能谱分析仪(EDS），对通过真空感应熔炼和电渣重熔双联工艺制备的GH3625合金电渣锭的显微组织及元素偏析情况进行分析和研究.同时，对铸态CH3625合金在不同温度下同一时间及同一温度下不同时间进行了均匀化处理.结果表明：GH3625合金电渣锭存在明显的枝晶间微观偏析，主要偏析元素为Nb、Mo等，形成富Nb的Laves相、MC 碳化物；不同元素的偏析程度为Nb>Mo>Ti>Al>Cr;Nb、Mo、Ti、AI在枝晶间大量富集，使得Laves等多种非平衡相在枝晶间析出；在均匀化过程中，随着均匀化温度的升高和时间的延长，偏析元素逐渐扩散均匀；当热处理制度为1130“Cx32h时，元素偏析
基本消除;Laves相体积分数随均匀化处理时间呈明显指数函数特征，V130=0.0335exp(-0.1631r)。关键词：GH3625合金；显微偏析；均匀化处理;Laves相；碳化物
中图分类号：TG142.71
文章编号：10050299(2016)060014-06
文献标志码：A
MicrosegregationandhomogenizationofGH3625alloyingot DING Yutian, LI Haifeng, WANG Wei, LIU Jianjun, GUO Tingbiao, HU Yong
( State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals( Lanzhou University of Technology) ,
Lanzhou730050，China)
Abstract : To eliminate the micro-segregation, improve the hot workability, and establish the uniform dynamics and formulate the homogenization schedule of cast GH3625 alloy, microstructure and element segregation of as cast GH 3625 alloy after vacuum induction melting (VIM) and electroslag remelting (ESR) was studied by means of Image-Pro Plus, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Cast GH 3625 alloy was homogenized at different temperatures or different time. The results show that GH 3625 alloy exhibits dendritic segregation, in which Nb and Mo are mainly segregation elements, and they formed Nb-rich Laves phase and MC carbides. The elements displayed different segregation degree as the following sequence: Nb> Mo> Ti> Al> Cr. Nb, Mo, Ti, and Al are largely enrichedenriched in the inter-dendrite, resulting in the precipitation of Laves and other non-equilibrium phases .The elements diffused more evenly during homogenization, as the homogenization temperature increases or the time prolongs. The element segregation of the GH 3625 alloyalmost eliminated after homogenization treatment at 1 130 °C for 32 h. Laves phase volume fraction and the homogenization time obey the following exponential function relation : Vl 130 =0.033 5exp( -0.163 1t).
Keywords: GH 3625 alloy; micro-segregation; homogenization; Laves phase; carbide
GH3625合金是20世纪50年代发展起来的，在650℃以下具有优异的高温蠕变性能、持久收稿日期：2016-03-08.
基金项目：国家自然科学基金项目（51661019）；甘肃省重大科技
专项项目（145RTSA004）.
作者简介：丁雨田（1962一），男，教授，博士生导师，通信作者：李每数据ail：xfeytg@163.com
性能、抗氧化和抗腐蚀性能[1-4].在低温~1095℃ 具有良好的强度和韧性[5-7]，被广泛应用于工业燃气轮机、核动力设备、化工厂和海水专用设备的管道系统，是航空、航天、核能、石油和化工等工业关键的零件材料[8-9].GH3625合金是一种以钼（Mo）和锯（Nb）为主要强化元素的固溶强化型镍基变形高温合金，其合金化程度高，含有大量的