碳含量对C-276合金组织及晶间腐蚀敏感性的影响  

Effect of carbon content on microstructure and intergranular corrosion susceptibility of C-276 alloy

作　　者：李艳美 王明家 张斌[1] 张爽 刘聪 马忠仁 万志永 LI Yanmei;WANG Mingjia;ZHANG Bin;ZHANG Shuang;LIU Cong;MA Zhongren;WAN Zhiyong(Qinhuangdao Hecheng Nickle Co.,Ltd.,Qinhuangdao 066200,Hebei,China;Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,Hebei,China;CITIC Dicastal Co.,Ltd.,Qinhuangdao,Qinhuangdao 066011,Hebei,China)

机构地区：[1]秦皇岛核诚镍业有限公司,河北秦皇岛066200 [2]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004 [3]中信戴卡股份有限公司,河北秦皇岛066011

出　　处：《有色金属科学与工程》2020年第4期56-63,共8页Nonferrous Metals Science and Engineering

摘　　要：选取不同碳含量的C-276合金板材样品,先对样品进行固溶处理,随后在900℃下进行不同时间的敏化处理。采用ASTM G28中A法,对固溶及敏化后的C-276样品进行晶间腐蚀敏感性试验,得出C-276材料的晶间腐蚀年腐蚀率随敏化时间的增加而增加,即延长敏化时间会增加C-276合金的晶间腐蚀敏感性。固溶状态下,高碳型C-276合金晶间腐蚀敏感性高于低碳型C-276合金;而在900℃敏化30 min以后,低碳型C-276合金呈现出更高的晶间腐蚀敏感性。采用金相显微镜和扫描电镜(SEM)研究碳含量对C-276合金显微组织的影响,固溶态下,低碳型合金晶界和晶粒内部均未发现有明显析出相,而高碳型C-276合金在部分晶界和晶粒内部分布着颗粒状富含Mo的析出相μ相。敏化过程中,无论低碳还是高碳型C-276合金,其析出相均为富含Mo的M6C型碳化物。高碳型C-276合金中,由于μ相对Mo元素起到钉扎作用,导致富含Mo的碳化物析出速度减缓,因此在敏化后,高碳型C-276合金具有更低的晶间腐蚀敏感性。Samples of different carbon content C-276 alloy plate were selected.The samples were solution treated first,and then sensitized at 900℃for different times.The method A of ASTM G28 was used to test the intergranular corrosion of C-276 samples with solution and sensitization.The results showed that the annual corrosion rate of C-276 alloy increased with the increase of sensitization time,and the intergranular corrosion sensitivity of C-276 alloy increased with the increase of sensitization time.The intergranular corrosion sensitivity of high carbon type C-276 alloy is higher than that of low carbon type C-276 alloy in solid solution state.After sensitization at 900℃for 30 minutes,low carbon C-276 alloy shows higher intergranular corrosion sensitivity.The effect of carbon content on the microstructure of C-276 alloy was studied by metallographic microscope and scanning electron microscope(SEM).In the solution state microstructure of low carbon C-276 alloy,no obvious precipitates were found at the grain boundary and inside the grains.In the solution state microstructure of high carbon C-276 alloy,the precipitated phaseμphase rich in Mo is distributed in part of the grain boundary and inside the grain.No matter low carbon or high carbon C-276 alloy,the precipitated phase in sensitization process is Mo rich M6C carbide.In the high carbon C-276 alloy,the precipitation rate of Mo rich carbides is slowed down due to the pinning effect ofμon Mo.Therefore,low carbon C-276 alloy has higher intergranular corrosion sensitivity after sensitization.

关 键 词：C-276合金 敏化处理 晶间腐蚀 碳化物 析出相 

分 类 号：TG174.2[金属学及工艺—金属表面处理]