Microstructure evolution of 55Ni−23Cr−13Co nickel-based superalloy during high-temperature cyclic deformation  

55Ni-23Cr-13Co基合金在高温循环变形中的显微组织演变

作　　者：Kai-meng WANG Hong-yang JING Lian-yong XU Lei ZHAO Yong-dian HAN Hai-zhou LI Kai SONG 王楷萌;荆洪阳;徐连勇;赵雷;韩永典;李海舟;宋恺(天津大学材料科学与工程学院,天津300350;天津市现代连接技术重点实验室,天津300350)

机构地区：[1]School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China [2]Tianjin Key Laboratory of Advanced Joining Technology,Tianjin 300350,China

出　　处：《Transactions of Nonferrous Metals Society of China》2021年第11期3452-3468,共17页中国有色金属学报（英文版）

基　　金：financial supports from the National Natural Science Foundation of China (Nos. 52025052, 51975405)。

摘　　要：The cyclic deformation behavior and microstructure evolution of the 55Ni−23Cr−13Co nickel-based superalloy were studied at 750℃ under the strain amplitudes from 0.35%to 0.6%.Coffin−Manson−Basquin and Smith−Watson−Topper relationships were employed,which satisfactorily predicted the fatigue life of the alloy under various strain amplitudes.The superalloy showed an initial cyclic hardening as a result of the interaction between the dislocations and the precipitates,and following cyclic softening behavior mainly due to the shearing of theγ′phase by dislocations and dislocations recovery under all strain amplitudes.Microstructure analyses showed that the M_(23)C_(6) carbides exhibited a continuous-chain distribution at lower strain amplitudes,while they showed a discontinuous distribution at higher strain amplitudes.As the strain amplitude increased,the size of theγ′phase decreased as the consequence of repeated shearing by dislocations.Fracture mechanisms were analyzed.Under higher strain amplitudes,cavities preferred to form around grain boundaries.通过750℃低周疲劳试验,研究55Ni-23Cr-13Co基高温合金在应变幅度为0.35%~0.6%下的循环变形行为及显微组织演变。Coffin-Manson-Basquin和Smith-Watson-Topper模型能很好地预测该合金不同应变幅度下的疲劳寿命。在循环加载过程中,该合金表现出现循环硬化后再循环软化的特征。初始循环硬化行为是由于位错与析出物的相互作用,而循环软化行为是由位错切割γ′相和位错回复引起的。显微组织分析结果表明,M_(23)C_(6)碳化物在较低应变幅度下呈连续链状分布,而在较高的应变幅度下呈不连续分布。由于位错对γ′相的重复剪切作用,随着应变幅度的增大,γ′相的尺寸减小。分析断裂机制,在较高的应变幅度下,孔洞容易在晶界附近形成。

关 键 词：nickel-based superalloy MICROSTRUCTURE low cycle fatigue PRECIPITATE 

分 类 号：TG132.3[一般工业技术—材料科学与工程]