分步退火及初始晶粒对Hastelloy C-276合金晶界特征分布影响  

Effects of Two-Step Annealing and Initial Grain Size on the Grain Boundary Character Distributions of Hastelloy C-276

作　　者：张晓宇[1,2] 赵宪明[1] 李德富[2] 郭胜利[2] ZHANG Xiao-yu;ZHAO Xian-ming;LI De-fu;GUO Sheng-H(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819, China;Center for Composites, General Research Institute for Non-ferrous Metals, Beijing 100088, China.)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819 [2]北京有色金属研究总院复合材料中心,北京100088

出　　处：《东北大学学报（自然科学版）》2018年第5期630-632,648,共4页Journal of Northeastern University(Natural Science)

基　　金：国家自然科学基金资助项目(51205028)

摘　　要：不同初始晶粒尺寸的Hastelloy C-276合金经冷轧变形后,分别采用一次退火和二次退火方法进行热处理,其晶界特征分布采用电子背散射衍射技术进行表征.结果表明,初始较大晶粒组织有利于晶界特征分布的优化,特殊晶界比例比小尺寸晶粒组织提高了近10%,达到了78.8%,同时形成了平均尺寸为200μm晶粒团簇组织.在相同晶粒尺寸条件下,采用二次退火工艺可以明显改善合金的晶界特征分布,∑3n晶界比例得到较大幅度的提高,并形成了良好的团簇组织.这是由于较多的非共格∑3晶界,容易产生∑9和∑27晶界,从而形成更多的三叉晶界,阻断了大角度晶界的连通性.Hastelloy C-276 samples with different initial grain sizes were subjected to one-step and two-step annealing heat treatments after cold-rolling process and their grain boundary character distributions（ GBCDs） were characterized by electron backscatter diffraction（ EBSD） techniques. The results showthat the large-sized initial grains tend to optimize the GBCD. Compared with that in the small-sized grain ones,the fraction of coincident site lattice（ CSL） boundary in Hastelloy C-276 samples with large-sized initial grains increases nearly 10%,which is up to 78. 8%. Meanwhile,the clusters with average size of 200 μm are formed. For the samples with same-sized grains,the GBCD can be well improved by the two-step annealing treatment,where the fraction of ∑3 nboundaries can be increased significantly and the better clusters can be formed. The more incoherent ∑3 boundaries,the more ∑9 and ∑27 boundaries can be generated,leading to the more triple junctions. Therefore,the connectivity of the high-angle grain boundary network is disrupted effectively.

关 键 词：二次退火热处理 初始晶粒 HASTELLOY C-276合金 特殊晶界 晶界特征分布 

分 类 号：TG111.7[金属学及工艺—物理冶金]