Effect of Processing Speed on Microstructures and Mechanical Properties of Submerged Friction Stir Processed AZ91 Alloy
Normal and submerged friction stir processing (SFSP) were conducted to AZ91 magnesium alloy plates with 6mm in thickness,and influence of processing speed (ν) on microstructures and mechanical properties of the experimental materials was investigated.The results revealed that fine and equiaxed grains were observed in the stirred zone (SZ).As the processing speed increased from 60mm/min to 150mm/min,the average grain size in the SZ of normal FSP material decreased.However,the grain size of the SFSP specimens first increased with the processing rate increasing from 60mm/min to 120mm/min,and then decreased when the processing rate increased to 150mm/min.Microstructure of the SFSP specimen was much finer compared with the normal FSP one,and the grain size of ?-Mg was about 1.2μm when the processing speed was 60mm/min during SFSP.Because of much finer microstructure of SFSP,the microhardness,tensile strength and elongation were all improved.SEM fracture observation showed that fine dimples and tearing edges could be observed on SFSP specimen which showing good ductility.In addition,high temperature tensile tests showed that SFSP AZ91 alloys exhibited excellent superplasticity at high strain rate,with an elongation of 1202% at 623 K with a strain rate of 3x10-3s-1.The present study demonstrated that SFSP possesses great potential in preparing fine-grained materials.
AZ91 magnesium alloy Submerged friction stir processing Microstructure Mechanical property
Fang Chai Datong Zhang Wen Zhang Cheng Qiu
National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China
国际会议
the Chinese Materials Congress 2012(2012年中国材料大会(CMC2012))
太原
英文
276-281
2012-07-13（万方平台首次上网日期，不代表论文的发表时间）