摘要
在室温下利用分离式霍普金森压杆对Al_(0.4)CoCrFeNi高熵合金帽型试样进行动态加载,研究了不同应变速率下Al_(0.4)CoCrFeNi高熵合金的绝热剪切敏感性。结果表明,动态加载前后Al_(0.4)CoCrFeNi高熵合金的晶粒尺寸分别约为100μm、100 nm,相差约3个数量级,动态加载后细小的晶粒尺寸使Al_(0.4)CoCrFeNi高熵合金具有更低的绝热剪切敏感性;Al_(0.4)CoCrFeNi高熵合金绝热剪切敏感性随应变速率增加而增加,在实验范围内,应变速率3 360 s-1时绝热剪切敏感性最高,产生了与动态加载方向成45°、宽约2μm的绝热剪切带,此时临界应变值和单位体积绝热剪切形成能也最小。Al_(0.4)CoCrFeNi高熵合金在高应变率变形过程中晶粒发生明显细化。Al_(0.4)CoCrFeNi高熵合金在动态加载下的绝热剪切归结为材料的热-黏塑性本构失稳。
The cap specimens of Al_(0.4)CoCrFeNi high-entropy alloy were dynamically loaded with a split Hopkinson pressure bar at room temperature, for studying the adiabatic shear sensitivity of Al_(0.4)CoCrFeNi high-entropy alloy at different strain rates. The results show that the grain size of Al_(0.4)CoCrFeNi high entropy alloy before and after dynamic loading is about 100 μm and 100 nm, respectively, with about three orders of magnitude difference. The Al_(0.4)CoCrFeNi high entropy alloy, with a finer grain size after dynamic loading, has lower adiabatic shear sensitivity, which will increase with the increase of strain rate. Within the range in the experiment, the adiabatic shear sensitivity reaches the highest when the strain rate is 3 360 s-1, forming an adiabatic shear band that is about 2 μm wide and has an angle of 45° with the dynamic loading direction. At this moment, both the critical strain value and the formation energy per unit volume of adiabatic shear are the smallest. The Al_(0.4)CoCrFeNi high-entropy alloy undergoes significant grain refinement during high strain rate deformation. And the adiabatic shear of Al_(0.4)CoCrFeNi high-entropy alloy under dynamic loading is attributed to the thermal-viscoplastic constitutive instability of the material.
作者
刘小刚
姜丽红
刘征
杨亮
郭正华
LIU Xiaogang;JIANG Lihong;LIU Zheng;YANG Liang;GUO Zhenghua(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,Jiangxi,China)
出处
《矿冶工程》
CAS
北大核心
2023年第1期133-136,共4页
Mining and Metallurgical Engineering
基金
江西省重大科技研发专项项目(20194ABC28001)
南昌航空大学研究生创新专项资金项目(2030009412138)。
