Effects of AlCoCrFeNiTi high-entropy alloy on microstructure and mechanical properties of pure aluminum
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2020年第17期
论文作者：Qinglin Li Shang Zhao Xuepeng Bao Yushi Zhang Yuqian Zhu Chuangzao Wang Yefeng Lan Yuxin Zhang Tiandong Xia
文章页码：1 - 11
摘 要：A new kind of AlCoCrFeNiTi high-entropy alloy（HEA） as a grain refiner was prepared by vacuum arc melting. In this work, the effects of HEA（1.0 wt.%, 2.0 wt.% and 3.0 wt.%） on the microstructure and mechanical properties of pure aluminum were studied. The microstructure was characterized and examined by scanning electron microscope（SEM）, energy dispersive X-ray spectroscopy（EDS）, X-ray diffraction（XRD）,electron probe micro-analyzer（EPMA） and transmission electron microscopy（TEM） to indicate the refining abilities and mechanism of HEA on pure aluminum. Results show that the addition of HEA refined both the macrostructure and microstructure of pure aluminum. When 1.0 wt.% HEA was added, most coarse columnar grains were refined into equiaxed crystals, and as the amount of HEA increased to 2.0 wt.% and3.0 wt.%, aluminum grains were further refined, and the grain boundaries were nearly indistinguishable.Moreover, the morphology of α-Al transformed from coarse columnar crystals to equiaxed grains, and the mean size of α-Al grains decreased from 374 μm to 27 μm. The Al3Ti, Al3Ni, and nano-phase precipitated from the aluminum alloy with HEA in the solidification. The typical rod-like nano-phases distributed interdendritic regions of α-Al. The average length of nano-phases is 2568 nm, 4372 nm, and 6907 nm and the average diameter is 112 nm, 103 nm, and 92 nm when 1.0 wt.%, 2.0 wt.% and 3.0 wt.% HEA were added to the pure aluminum, respectively. The ultimate tensile strength（UTS） and yield strength（YS）were improved in all samples, whereas the elongation（El） was decreased with increasing HEA concentration. When 3.0 wt.% HEA was added into the aluminum melt, the UTS was improved by 145.2% from62 MPa to 152 MPa, the YS was increased by 173.8% from 42 MPa to 115 MPa, and the El was decreased by 33.3% from 39% to 26%.
Qinglin Li1,2，Shang Zhao1,2，Xuepeng Bao1,2，Yushi Zhang1,2，Yuqian Zhu1,2，Chuangzao Wang1,2，Yefeng Lan1,2，Yuxin Zhang1,2，Tiandong Xia1,2
1. School of Materials Science and Engineering, Lanzhou University of Technology2. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology
摘 要：A new kind of AlCoCrFeNiTi high-entropy alloy（HEA） as a grain refiner was prepared by vacuum arc melting. In this work, the effects of HEA（1.0 wt.%, 2.0 wt.% and 3.0 wt.%） on the microstructure and mechanical properties of pure aluminum were studied. The microstructure was characterized and examined by scanning electron microscope（SEM）, energy dispersive X-ray spectroscopy（EDS）, X-ray diffraction（XRD）,electron probe micro-analyzer（EPMA） and transmission electron microscopy（TEM） to indicate the refining abilities and mechanism of HEA on pure aluminum. Results show that the addition of HEA refined both the macrostructure and microstructure of pure aluminum. When 1.0 wt.% HEA was added, most coarse columnar grains were refined into equiaxed crystals, and as the amount of HEA increased to 2.0 wt.% and3.0 wt.%, aluminum grains were further refined, and the grain boundaries were nearly indistinguishable.Moreover, the morphology of α-Al transformed from coarse columnar crystals to equiaxed grains, and the mean size of α-Al grains decreased from 374 μm to 27 μm. The Al3Ti, Al3Ni, and nano-phase precipitated from the aluminum alloy with HEA in the solidification. The typical rod-like nano-phases distributed interdendritic regions of α-Al. The average length of nano-phases is 2568 nm, 4372 nm, and 6907 nm and the average diameter is 112 nm, 103 nm, and 92 nm when 1.0 wt.%, 2.0 wt.% and 3.0 wt.% HEA were added to the pure aluminum, respectively. The ultimate tensile strength（UTS） and yield strength（YS）were improved in all samples, whereas the elongation（El） was decreased with increasing HEA concentration. When 3.0 wt.% HEA was added into the aluminum melt, the UTS was improved by 145.2% from62 MPa to 152 MPa, the YS was increased by 173.8% from 42 MPa to 115 MPa, and the El was decreased by 33.3% from 39% to 26%.
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