DD8单晶镍基高温合金的热机械疲劳  

THERMO-MECHANICAL FATIGUE BEHAVIOURS OF DD8 SINGLE CRYSTAL NICKEL BASE SUPERALLOY

作　　者：王跃臣[1] 李守新[1] 艾素华[1] 刘峰[1] 孙晓峰[1] 管恒荣[1] 王中光[1] 

机构地区：[1]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》2003年第9期903-907,共5页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展规划资助项目 G19990650

摘　　要：对DD8合金进行了同位相(IP)与反位相(DP)热机械疲劳(TMF)实验.结果表明:当以机械应变幅作为参量时,在高应变幅下,IP疲劳寿命均低于OP的寿命;随着应变幅的降低,IP疲劳寿命有向OP寿命靠近的趋势.扫描电镜观察表明,IP和OP TMF试样的断口形貌有明显的不同.在IP实验中,裂纹萌生于试样内的铸造孔洞,垂直于加载轴方向扩展;而OP裂纹则是萌生于试样的自由表面,沿着{111}晶面扩展.不同的裂纹萌生和扩展机制是导致IP和OP TMF寿命差异的主要原因.The experiment of thermo-mechanical fatigue (TMF) behavior of superalloy DD8 shows that when the mechanical strain range is taken as the basis, the life of in phase (IP) TMF is less than that of out of phase (OP) TMF at higher strain ranges. However, with decreasing the strain range, the life of IP TMF is approaching to that of the OP TMF. SEM reveals that there is an obvious difference in the crack morphology of IP and OP TMF samples. In IP TMF, cracks initiated at internal pores and propagated vertically to the loading axis. In OP TMF, the crack initiated at the free surface of samples and propagated alone {111} plane. Different behaviors of crack initiated and propagated are main reason causing the different lifes of IP and OP TMF.

关 键 词：单晶镍基高温合金 同位相 反位相 热机械疲劳 

分 类 号：TG111.8[金属学及工艺—物理冶金] TG132.3[金属学及工艺—金属学]