Influences of Asymmetric Reduction Rolling on the Microstructure and Mechanical Properties of AZ91

Yi-Quan Zhao¹，Hong-Mei Chen²，Jing Zhang³，Ru Ma¹，Yan-Dong Liu⁴，Yi-Nong Wang¹，Ling Wang⁵，Qun Zhang⁶，Wei-Gang Li⁶

1. School of Materials Science and Engineering, Dalian University of Technology2. Provincial Key Lab of Advanced Welding Technology,Jiangsu University of Science and Technology3. School of Metallurgy and Materials Engineering, Jiangsu University of Science and Technology4. School of Materials Science and Engineering, Northeastern University5. Yingkou Institute of Technology6. Bayuquan Entry-Exit Inspection and Quarantine Bureau

摘 要：The influence of asymmetric reduction rolling(ARR) on the microstructure, texture and mechanical properties of AZ91 was investigated. The microstructural characteristics of the AZ91 sheet processed by symmetric rolling(SR) were the twins, intersection of twins and dynamic recrystalization(DRX) grains around the coarse grains and within the twins.However, the amount of twins and DRX grains in ARRed AZ91 was much smaller than that in SRed AZ91. The SRed AZ91 after annealing exhibited fine DRX grains and some coarse grains with a size of * 100 lm. The grains in ARRed AZ91 after annealing were much finer and more homogeneous than those in SRed AZ91 after annealing. The intensity of basal texture of ARRed AZ91 after annealing was lower than that of SRed AZ91 rolling after annealing. The average Schmid factor of ARRed AZ91 is 0.34, which is higher than that of SRed AZ91. The yield strength and ultimate tensile strength of the ARRed AZ91 sheet were increased to 16.1% and 31.8% compared to SRed AZ91 sheet, from 155 to180 MPa, and from 220 to 290 MPa, respectively. The improvement of mechanical properties in ARRed AZ91 after annealing was attributed to much finer, more homogeneous DRX grains and weaker basal texture.

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