冷轧+退火对CoCrNi中熵合金显微组织和力学性能的影响

Effect of cold-rolling and annealing on microstructure and mechanical properties of CoCrNi medium-entropy alloy

研究了CoCrNi中熵合金分别经低温(-196℃)和室温(25℃)冷轧及分别700℃和800℃退火后的显微组织和力学性能。结果表明,合金经低温冷轧+700℃退火后具有优良的强度-韧性匹配,抗拉强度为1023 MPa,总延伸率为34%,相比于室温冷轧+700℃退火、低温冷轧+800℃退火和室温冷轧+800℃退火,其抗拉强度分别提高了16%、13%、37%,主要是由于试样内发生回复与再结晶产生退火孪晶,细化晶粒,减小位错密度,阻碍位错的移动,提高合金强度。

Microstructure and mechanical properties of CoCrNi medium-entropy alloy were investigated after cold-rolling at cryogenic temperature(-196℃)and room temperature(25℃)and annealing at 700℃and 800℃.The results show that the alloy has an excellent match of strength and toughness after cold-rolling at-196℃+annealing at 700℃,with tensile strength of 1023 MPa and total elongation of 34%.Compared with that after cold-rolling at 25℃+annealing at 700℃,cold-rolling at 25℃+annealing at 800℃,and cold-rolling at-196℃+annealing at 800℃,the tensile strength increases by 16%,13%and 37%,respectively.This is mainly due to the annealing twins produced by recovery and recrystallization in the specimen,which refines the grain,reduces the dislocation density,hinders dislocation movement and improves the strength of the alloy.