| SHANG Zhijian,WANG Wenqin,ZHU Xun,WANG De,CHEN Yunxia,PEI Xingqi,HUANG Wei,CHEN Jigen,XU Yongdong.Effects of Resistance Seam Welding and Rolling on Microstructure and Mechanical Properties of AlCoCrFeNi2.1 Eutectic High-entropy Alloy[J],54(11):195-202 |
| Effects of Resistance Seam Welding and Rolling on Microstructure and Mechanical Properties of AlCoCrFeNi2.1 Eutectic High-entropy Alloy |
| Received:November 05, 2024 Revised:April 07, 2025 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.11.016 |
| KeyWord:resistance seam welding and rolling HDI hardening wear rate mechanical property |
| Author | Institution |
| SHANG Zhijian |
School of Advanced Manufacturing, Nanchang University, Nanchang , China |
| WANG Wenqin |
School of Advanced Manufacturing, Nanchang University, Nanchang , China |
| ZHU Xun |
School of Advanced Manufacturing, Nanchang University, Nanchang , China |
| WANG De |
School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang , China |
| CHEN Yunxia |
School of Intelligent Manufacturing and Control Engineering, Shanghai Polytechnic University, Shanghai , China |
| PEI Xingqi |
School of Advanced Manufacturing, Nanchang University, Nanchang , China |
| HUANG Wei |
School of Advanced Manufacturing, Nanchang University, Nanchang , China |
| CHEN Jigen |
School of Advanced Manufacturing, Nanchang University, Nanchang , China |
| XU Yongdong |
School of Advanced Manufacturing, Nanchang University, Nanchang , China |
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| Abstract: |
| This study explores the effects of resistance seam welding and rolling on the microstructure and mechanical properties of AlCoCrFeNi2.1 eutectic high-entropy alloy (HEA), aiming to enhance its comprehensive mechanical properties. Optimal rolling parameters are identified via orthogonal experiments at a welding current of 3000 A, a welding speed of 1 mm/s for 10 rolling passes. Specimens in both as-cast and rolled conditions are prepared for detailed analysis. The phase composition and surface microstructure of the alloy before and after rolling are comparatively analyzed by means of an X-ray diffractometer (XRD), a field emission scanning electron microscope (SEM) and an energy dispersive spectrometer (EDS). The results show that after the rolling treatment, the alloy still maintains a dual-phase structure of body-centered cubic (BCC) and face-centered cubic (FCC). However, the non-thermal effect of the electrical pulse during the rolling process promotes the diffusion of elements, leading to a decrease in the content of Al, which is a stabilizer of the BCC phase, and thus promoting the transformation of the BCC phase into the FCC phase. Meanwhile, the thermal effect of the electrical pulse causes the alloy to soften, and in combination with the rolling pressure, it refines the grains and reduces the lamellar spacing of the eutectic phase by 25.8%. The hardness test results show that the surface hardness of the as-cast specimen is 264.3HV, and it increases by 25.4% after the rolling treatment. The friction and wear performance test indicates that after the rolling treatment, the average coefficient of friction (COF) of the specimen decreases from 0.549 4 to 0.514 8, and the average wear rate also decreases from 2.74×10−6 mm³/(N.m) to 2.32×10−6 mm³/(N.m). The rolled specimen exhibits superior wear resistance. The wear analysis shows that the wear mechanisms of the as-cast specimen under the action of the ZrO2 grinding ball are mainly abrasive wear and oxidative wear. The non-thermal effect of the pulse current during the rolling process homogenizes the element diffusion, forming a dispersed oxide film, which reduces the direct contact between the grinding ball and the specimen. Together with the work hardening caused by rolling, it improves the wear resistance, which is consistent with the decrease in the friction coefficient and average wear rate. The tensile test results show that the yield strength, tensile strength and elongation of the as-cast alloy are 741.83 MPa, 1 011.63 MPa and 17.86% respectively. After the rolling treatment, the yield strength increases to 966.87 MPa, the tensile strength increases to 1 343.24 MPa, and the elongation increases to 28.81%, which are 30.34%, 32.78% and 61.31% higher than those of the as-cast alloy respectively. The fracture mode also changes from a mixed ductile-brittle fracture of the as-cast specimen to a single ductile fracture. The synergistic improvement of strength and toughness mainly stems from the coupling effect of the pressure and the electrical pulse (thermal and non-thermal effects) during the rolling process, which promotes the Heterogeneous Deformation Induced (HDI) hardening and increases the long-range back stress and positive stress. In conclusion, the resistance seam welding and rolling treatment can improve the strength and wear resistance of the AlCoCrFeNi2.1 alloy without reducing its plasticity. It provides important reference value for the optimization of the microstructure and the improvement of the performance of high-entropy alloys. |
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