Acta Metallurgica Sinica (English Letters) ›› 2024, Vol. 37 ›› Issue (7): 1135-1146.DOI: 10.1007/s40195-024-01692-2

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Effect of Room Temperature Ultrasonic Vibration Compression on the Microstructure Evolution and Mechanical Properties of AZ91 Alloy

Ziyue Xu1, Huan Liu1,2(), Luyao Li3, Chao Sun4, Xi Tan4, Baishan Chen5, Qiangsheng Dong6, Yuna Wu1, Jinghua Jiang1, Jiang Ma1()   

  1. 1College of Materials Science and Engineering, Hohai University, Nanjing 210000, China
    2Suzhou Research Institute of Hohai University, Suzhou 215000, China
    3Shenzhen Key Laboratory of High Performance Nontraditional Manufacturing, College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen 518060, China
    4Institute of Medical Devices (Suzhou), Southeast University, Suzhou 215163, China
    5Institute for Advanced Study, Central South University, Changsha 410083, China
    6Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing Institute of Technology, Nanjing 211167, China
  • Received:2023-11-07 Revised:2024-01-23 Accepted:2024-01-26 Online:2024-04-09 Published:2024-04-09
  • Contact: Huan Liu, Jiang Ma

Abstract:

To investigate the potential of direct ultrasonic vibration on improving the performance of magnesium alloys, this study first employed the ultrasonic vibration compression (UVC) on the solid solution treated AZ91 alloy, and explored its microstructure evolution and mechanical properties under UVC. Within only two seconds, the UVC alloys showed large deformation strains of 34.8-54.4%, and sudden increase of sample temperature to 243 °C. Microstructure characterizations proved that UVC promoted the formation of abundant shear bands, fine grains, and the bimodal distribution of Mg17Al12 precipitates consisting of submicron particles located within the shear bands and nano-sized ones within the matrix. Owing to the unique microstructure, the micro-hardness (and nano-hardness) value of UVC alloy was increased by 37.7% (35%) when compared with the solution-treated alloy. Moreover, the nano-modulus of the developed AZ91 alloy was also significantly increased to 62 GPa by statistical nanoindentation tests, which could be ascribed to increased Mg17Al12 precipitates and decreased c/a value to some extent. In general, this work provides a new insight into the design and preparation of high-performance magnesium alloys by UVC at room temperature.

Key words: AZ91 alloys, Ultrasonic vibration compression, Precipitation, Shear bands, Mechanical properties