Experimental investigation of a Portevin-Le Chatelier band in Ni-Co-based superalloys in relation to γ' precipitates at 500 °C
Experimental investigation of a Portevin-Le Chatelier band in Ni-Co-based superalloys in relation to γ' precipitates at 500 °C
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DOI：
10.1016/j.jmst.2020.02.001
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发表时间：
2020
影响因子：
10.9
通讯作者：
Zhang Qingchuan
中科院分区：
文献类型：
--
作者：
Liu Yanke;Cai Yulong;Tian Chenggang;Zhang Guoliang;Han Guoming;Fu Shihua;Cui Chuanyong;Zhang Qingchuan
采用原位法研究了不同γ'相含量的Ni-Co基高温合金在500 °C、1×10~（-4）s~（-1）条件下的宏观局部化变形行为，数字图像相关分析（DIC）的结果表明，应力-应变曲线的锯齿状流动，应变曲线上存在局部变形，断口形貌以穿晶断裂为主，断口上有大量韧窝在低γ'含量的合金中，发生沿晶断裂，断裂截面较大;在高γ'含量的合金中，发生Portevin-Le Chatelier（PLC）效应;高γ'含量的合金的局部化变形比低γ'含量的合金严重，且带宽略大;此外，首次发现，在高γ'含量的合金中观察到一种特殊的传播特征，即以头尾相连为特征的±60°锯齿形带。
The macroscopically localized deformation behaviors of Ni-Co-based superalloys with different γ' precipitate content were investigated at 500 °C and 1×10~(–4) s~(–1) via an in situ method namely, digital image correlation(DIC).The DIC results showed that the serrated flow of the stress-strain curves was accompanied by localized deformation of the specimens.The fracture morphology was characterized mainly by transgranular fracture with numerous dimples in the low γ' content alloy, and intergranular fracture with large fracture section in the high γ' content alloy.The Portevin-Le Chatelier(PLC)effect occurred in the investigated Ni-Co-based superalloys.Furthermore, the localized deformation of the high γ' content alloy was more severe than that of the low γ' content alloy, and the band width was slightly larger.Moreover, for the first-time ever, a special propagation feature, namely ±60° zigzag bands characterized by head-to-tail connections, was observed in the high γ' content alloy.