K4169合金的高温低周疲劳行为  

Low-cycle Fatigue Behavior of a Cast Ni-based Superalloy K4169 at 650℃

作　　者：刘庆澳 张伟红[1,2] 王志远[1,2] 孙文儒 LIU Qingao;ZHANG Weihong;WANG Zhiyuan;SUN Wenru(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016

出　　处：《材料研究学报》2024年第8期621-631,共11页Chinese Journal of Materials Research

摘　　要：在650℃进行镍基铸造高温合金K4169的低周疲劳实验,使用SEM、TEM等手段表征合金变形前后的微观组织和断裂特征,研究了这种合金的高温低周疲劳行为。结果表明,这种合金的疲劳寿命随着应变的增大逐渐降低,应变为0.5%和0.6%时在循环前2~200周次内出现硬化现象,随后出现循环稳定和循环软化;应变为0.8%和1.0%时,合金出现连续的循环软化;初期的循环硬化与γ″强化相对位错运动的阻碍有关,而循环软化则归因于位错反复剪切γ″相。这种合金的塑性应变幅与疲劳失效反向数的Coffin-Manson方程表现出双线性关系。对微观变形结构的观察表明,这种合金在高应变和低应变下的循环变形模式均为位错剪切γ″相和滑移,且其在不同应变下的疲劳失效均表现为穿晶断裂。这种合金表现出双线性的原因可能是变形均匀性的转变,非Masing特性证明了这种转变。The low cycle fatigue behavior of nickel based cast superalloy K4169 at 650℃was studied,while its microstructure variation before and after test was assessed by means of SEM and TEM.The results show that the fatigue life of the alloy gradually decreases with the increasing strain.When the strain is 0.5%and 0.6%,the alloy experiences strain hardening within the early 2~200 cycles,followed by cyclic stability and cyclic softening,respectively;When the strain is 0.8%and 1.0%,the alloy exhibits continuous cyclic softening behavior;Initial cyclic hardening is related to the hindering effect ofγ″strengthening phases on the movement of dislocations,while cyclic softening is attributed to dislocations shearingγ″phases repeatedly.The Coffin-Manson equation for the relationship between the plastic strain amplitude and the reverse number of fatigue failure of the alloy exhibits a bilinear relationship.Observation of the microstructure shows that the cyclic deformation mode of the alloy at high and low strains is all dislocations shearingγ″phase and slip,and the fatigue failure of the alloy under different strains all exhibits transgranular fracture.Therefore,the reason for the bilinear behavior of the alloy may be the transformation of deformation uniformity,and the non-Masing characteristic exhibited by the alloy also demonstrate the transformation of deformation uniformity.

关 键 词：金属材料 K4169 合金 低周疲劳 断裂行为 Coffin-Manson 关系 变形机制 

分 类 号：TG146.15[一般工业技术—材料科学与工程]