中文摘要：

采用Bridgman技术研究在10, 30和150 μm/s抽拉速率下的一次定向凝固和10 μm/s抽拉速率下的二次定向凝固方法制备出的Al3CrCuFeNi2高熵合金,并对相应的金相显微组织进行分析; 采用EBSD技术对10 μm/s一次和二次定向凝固样品生长过程中的取向变化及晶界取向差角进行分析;对10 μm/s二次定向凝固样品和吸铸样品的室温拉伸力学性能进行研究. 结果表明,对比吸铸, 10, 30 和 150 μm/s定向凝固样品的组织形貌,10 μm/s定向凝固制备的样品枝晶一次间距最大, 枝晶干生长方向角度差最小;10 μm/s二次定向凝固的晶粒取向更接近〈001〉方向,且多数晶界取向差小于5°; 10 μm/s 二次定向凝固Al3CrCuFeNi2高熵合金样品比吸铸样品的屈服强度提高34.6%, 抗拉强度提高10.2%, 延伸率提高40%.

英文摘要：

The high-entropy alloy is a class of new metal material,its dominant element is generally more than three, and its mixing entropy is high and easy to form a solid solution structure. A large number of investigations show that high-entropy alloy possess excellent high temperature phase stability and softening resistance, which is superior to traditional superalloy. The Al3CrCuFeNi2 high-entropy alloy is studied by using once Bridgman solidification at different draw rates （10, 30 and 150 μm/s） and twice Bridgman solidification at 10 μm/s draw rate, the corresponding microstructure are analyzed. The EBSD technique is applied to detect the alloy growth orientation and grain boundary misorientation angle of alloys by once and twice Bridgman solidification at 10 μm/s draw rate. The room temperature tensile mechanical properties of Al3CrCuFeNi2 high-entropy alloy by twice Bridgman solidification at 10 μm/s draw rate and suction casting are studied. The results show that the primary spacing of dendritic of Al3CrCuFeNi2 high-entropy alloy by Bridgman solidification at 10 μm/s draw rate is larger than other draw rates and suction casting, while the growth orientation angle of dendrite dry is smaller than others. The orientation is close to the 〈001〉 direction after twice Bridgman solidification at 10 μm/s draw rate, and most of grain boundary misorientation angle are less than 5°. Compared with suction casting samples, yield strength, tensile strength and elongation of Al3CrCuFeNi2 high-entropy alloy by using twice Bridgman solidification increased by 34.6%, 10.2% and 40%.