基于γ′相尺寸的新型Ni-Cr-Co基合金的高温变形行为  

High Temperature Deformation Behavior of New Ni-Cr-Co Based Alloy Based on γ′ Phase Size

作　　者：丁雨田[1,2] 张宝兵 高钰璧 陈建军 闫康 张霞[1,2] 马元俊 Ding Yutian;Zhang Baobing;Gao Yubi;Chen Jianjun;Yan Kang;Zhang Xia;Ma Yuanjun(State Key Laboratory of Advaneed Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;School of Material Scicnce and Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050 [2]兰州理工大学材料科学与工程学院,甘肃兰州730050

出　　处：《稀有金属材料与工程》2022年第7期2490-2498,共9页Rare Metal Materials and Engineering

基　　金：国家重点研发计划(2017YFA0700703);国家自然科学基金(51661019);甘肃省科技重大专项(145RTSA004);兰州理工大学红柳一流学科建设计划。

摘　　要：本研究在600℃、5×10^(-4)s^(-1)条件下对不同γ′相尺寸的毫米级粗晶新型Ni-Cr-Co基合金进行高温拉伸实验,并结合OM,SEM和TEM研究γ′相尺寸对合金高温变形行为和锯齿流变效应的影响。结果表明,γ′相尺寸对合金力学性能影响显著,随着γ′相尺寸的增加,材料强度呈先提高后降低的趋势,合金的主要变形机制由位错切过γ′相转变为位错绕过γ′相;当γ′相尺寸持续增加时,位错运动受阻难以绕过γ′相,溶质原子钉扎可动位错,当应力增大至一定程度时位错脱钉,反复的钉扎与脱钉即动态应变时效导致合金在变形过程中出现锯齿流变效应,可通过调控γ′相尺寸弱化。当γ′相平均尺寸为57.18 nm时,锯齿流变效应微弱,临界应变最大,力学性能较高,因此γ′相最佳尺寸为57.18 nm。In this study, the high-temperature tensile tests were carried out on the millimeter-level coarse-grained new Ni-Cr-Co-based alloy with different γ′ phase sizes at 600 ℃ and 5×10^(-4)s^(-1), and the effects of γ′ phase sizes on the high-temperature tensile behavior and serrated flow effect of the alloy were studied by OM, SEM, and TEM. The results show that the size of γ′ phase has a significant effect on the mechanical properties of the alloy. With increasing of the size of γ′ phase, the strength of material increases at first and then decreases.The main deformation mechanism of the alloy changes from dislocation cutting through γ′ phase to dislocation by passing γ′ phase. When the size of γ′ phase continues to increase, the dislocation movement is blocked, and the dislocation is difficult to bypass the γ′ phase. The solute atoms can pin the movable dislocation. When the stress increases to a certain extent, the dislocation is depinning. Repeated pinning and depinning, that is to say, the dynamic strain aging leads to the serrated flow effect in the deformation process of the alloy, which can be weakened by adjusting the size of γ′ phase. When the average size of γ′ phase is 57.18 nm, the serrated flow effect is weak, the critical strain is the largest, and the mechanical properties become higher. Therefore, the optimal size of the γ′ phase is 57.18 nm.

关 键 词：Ni-Cr-Co基合金 γ′相 变形行为 位错 锯齿流变 

分 类 号：TG146.15[一般工业技术—材料科学与工程]