Microstructure evolution during high-temperature deformation of 8090 Al-Li alloy

作者：Xun Y; Tan MJ^*

来源：Materials and Manufacturing Processes, 2004, 19(3): 373-389.

DOI：10.1081/AMP-120038649

• Al-Li alloy
• superplasticity
• boundary character
• dynamic recrystallization
• elongation to failure
• electron backscattered diffraction
• microstructure
• misorientations
• grain boundary sliding
• dislocation
• thermomechanical processing
• microtexture
• facture
• mechanical property
• orientation imaging microscopy

The microstructure evolution of an as-processed 8090 Al-Li alloy during high temperature deformation has been investigated with emphasis on the dynamic grain size refinement and the formation of high-angle grain boundaries. Tensile tests were conducted at temperatures 470-560degreesC and initial strain rates of 10(-2)-10(-6)s(-1). The starting and deformed samples were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Electron Backscattered Diffraction (EBSD). The material showed a maximum elongation to failure of 660% at 530degreesC and strain rate of 10(-3)s(-1). A microstructural transformation from coarse grains to uniform fine microstructure through dynamic recrystallization (DRX) was observed. The DRX process was characterized by (1) a bimodal microstructure, (2) a gradual increase in average boundary misorientation angles, and (3) a gradual decrease of microtexture. The development of high angle boundaries was attributed to the absorption of dislocations into subboundaries and the grain boundary sliding (GBS)-induced subgrain rotation. The microstructural evolution was suggested to be responsible for the superplastic behavior observed in this as-processed material.

• 出版日期2004
• 单位南阳理工学院