Operating slip modes and inhomogeneous plastic deformation of Mg-10Gd-3Y-0.5Zr alloy during compression
(1. Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China;
2. Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
3. Shenyang National Laboratory for Materials Science, International Joint Laboratory for Light Alloys (Ministry of Education), College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
4. National Engineering Research Center of Light Alloys Net Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China)
2. Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
3. Shenyang National Laboratory for Materials Science, International Joint Laboratory for Light Alloys (Ministry of Education), College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
4. National Engineering Research Center of Light Alloys Net Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China)
Abstract: To understand the operating slip modes and inhomogeneous plastic deformation quantitatively and statistically for a high-performance cast Mg-10Gd-3Y-0.5Zr (wt.%, GW103) alloy during room-temperature uniaxial compression, detailed slip trace analysis and electron backscatter diffraction (EBSD) based misorientation analysis of this alloy in aged condition were carried out. After 2% plastic strain, according to relative frequency of identified slip traces, the active slip modes were basal áa？ slip (73.3%), followed by prismatic áa？ slip (15.8%), then second-order pyramidal ác+a？ slip (6.9%), and finally first-order pyramidal áa？ slip (4%). Although most of the active slip systems exhibited large Schmid factor (m) values (>0.3), it was worth noting that some hard-oriented (m<0.1) slip systems were also active. For most of the grain boundaries exhibiting extremely large geometrically necessary dislocation (GND) density, at least one of the following conditions was satisfied: large grain boundary misorientation angle (GBMA) and/or large deviation of mmax for particular slip mode between neighboring grains. The plastic heterogeneity of grains (magnitude/distribution of GND density) was independent of the visibility of slip traces. The grain orientation speared (GOS) and/or grain average GND density showed no obvious correlation with mmax (for particular slip mode).
Key words: Mg-RE alloy; operating slip mode; slip trace analysis; plastic deformation heterogeneity; geometrically necessary dislocation (GND) density