M38镍基高温合金高温低周疲劳性能及断裂机制  

LOW CYCLE FATIGUE PROPERTIES AND FRACTURE MECHANISMS OF M38 NICKEL BASE SUPERALLOY AT HIGH TEMPERATURE

作　　者：黄志伟[1] 袁福河[2] 王中光[2] 朱世杰[2] 王富岗[1] 

机构地区：[1]大连理工大学材料科学与工程学院,大连116023 [2]中国科学院金属研究所沈阳材料科学国家(联合)实验室,沈阳110016

出　　处：《金属学报》2007年第10期1025-1030,共6页Acta Metallurgica Sinica

基　　金：沈阳界面材料研究中心海外学者计划项目资助

摘　　要：对铸造镍基高温合金M38在900℃下的低周疲劳行为进行了研究.采取轴向总应变控制,应变比为-1,应变速率为1×10^(-2) s^(-1).实验结果表明:M38在900℃下具有与IN738LC接近的疲劳性能.在高应变幅时,疲劳裂纹主要萌生在表面碳化物等应力集中处;在低应变幅时,氧化对裂纹的萌生起重要作用,疲劳裂纹主要萌生于与试样表面相连的易氧化的富Cr晶界处和富Ti的碳化物处,在所有应变幅下,疲劳裂纹均沿垂直应力轴的方向穿晶扩展.Low cycle fatigue tests of the cast nickel base superalloy M38 have been conducted at 900 ℃ in air under fully reversed total strain control, strain ratio of -1 and the strain rate of 1 ×10^-2 s^-1. After failure, the fracture surfaces and longitudinal sections of the specimens were examined using SEM. Experimental results revealed that the fatigue property of M38 is similar to that of IN738LC. At high strain amplitudes, crack tended to initiate at the stress concentration sites such as surface carbides. While at low strain amplitudes, oxidation played an important role on crack initiation. The Cr-rich surface connected grain boundaries and Ti-rich surface carbides were observed to be favorable crack initiation sites. Under all strain amplitudes, the crack propagation modes were transgranular.

关 键 词：镍基高温合金 高温低周疲劳 断裂机制 裂纹萌生和扩展 

分 类 号：TG146.15[一般工业技术—材料科学与工程] V231.95[金属学及工艺—金属材料]