采用真空电弧熔炼炉制备一种γ'相强化型NiCoCrFeAlTiMoW合金,利用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱仪(EDS)及拉伸试验机研究合金在750,850,950℃下,经200 h长期时效后γ'相的粗化行为与力学性能的演变规律及机制.结果表明:随时效时间的延长,γ'相在时效过程中始终为球形,γ'相尺寸逐渐增大,且在750,850,950℃均发生凝并现象.合金具有较高的扩散激活能,其值为357 kJ/mol,这主要是由于基体为成分复杂的高熵固溶体,受迟滞扩散效应影响,Al,Ti原子在基体中的扩散变得困难.合金经750℃时效后屈服强度逐渐提高,经850℃时效后的屈服强度先升高后降低,经950℃时效后的屈服强度逐渐降低,合金屈服强度的改变是由γ'相尺寸增加导致合金的沉淀强化机制发生转变所引起的.
A γ'phase strengthened NiCoCrFeAlTiMoW alloy was prepared in a vacuum arc melting furnace,and X-ray diffractometer(XRD),scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and tensile testing machine were used to investigate the coarsening behavior and the evolution law and mechanism of mechanical properties of the γ'phase after 200 h long-term aging at 750,850℃and 950℃.The results show that γ'phase remains spherical during the aging process when the aging time is extended,γ'phase size gradually increases and the solidification phenomenon occurs at 750,850℃and 950℃.The alloy has a high diffusion activation energy with a value of 357 kJ/mol.This is mainly due to the fact that the matrix is a high entropy solid solution with complex composition,and the diffusion of Al and Ti atoms in the matrix becomes difficult due to the hysteresis diffusion effect.The yield strength of the alloy gradually increases after aging at 750℃,the yield strength after aging at 850℃first increases and then decreases,and gradually decreases after aging at 950℃.The change in the yield strength of the alloy is caused by the increase in the size of the γ'phase,which leads to a shift in the precipitation strengthening mechanism of the alloy.
刘继文;胡朝辉;王君阳;林雅婷;张璐
沈阳航空航天大学 材料科学与工程学院,沈阳 110136沈阳航空航天大学 材料科学与工程学院,沈阳 110136||沈阳航空航天大学 航空制造工艺数字化国防重点学科实验室,沈阳 110136
金属材料
γ'相粗化;高熵合金;力学性能;强化机制
γ'phase coarsening;high-entropy alloy;mechanical property;strengthening mechanism
《材料工程》 2024 (002)
172-179 / 8
沈阳航空航天大学航空制造工艺数字化国防重点学科实验室开放基金资助项目(SHSYS202205);沈阳航空航天大学大学生创新创业训练计划项目(X202210143007)
10.11868/j.issn.1001-4381.2023.000292
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