研究挤压温度对累积挤压工艺制备的异质结构Mg?1Gd/Mg?13Gd复合板显微组织和力学性能的影响.结果表明,当挤压温度为330℃时,Mg?1Gd/Mg?13Gd复合板在连续层之间形成明显的晶粒尺寸差异,随着挤压温度从380℃增加到430℃时,这种差异逐渐消失.此外,细晶层中再结晶晶粒的生长速度快于粗晶层.而且,Gd元素的扩散能力随着挤压温度的升高而增强,促进细晶层中析出相的增加和粗化.拉伸测试表明,380℃下的挤压试样具有优异的强度和塑性结合.这主要归因于粗、细晶层之间的不均匀织构、形变诱导强化和硬化的协同作用.细晶层有利于柱面
滑移的激活,而粗晶层有利于基面和锥面滑移的激活,尤其是在380℃时更为显著.锥面滑移的激活有助于协调进一步的塑性变形.
The influence of extrusion temperature on microstructure and mechanical properties of heterogeneous Mg?1Gd/Mg?13Gd laminate prepared by accumulated extrusion bonding was investigated. The results reveal that the Mg?1Gd/Mg?13Gd laminate forms a significant difference in grain size between the successive layers when extruded at 330 ℃, and this difference gradually disappears as the extrusion temperature increases from 380 to 430 ℃. Besides, the growth rate of recrystallized grains in fine-grained layers is faster than that in coarse-grained layers. Moreover, the diffusion ability of Gd element increases with elevating extrusion temperatures, promoting the increase and coarsening of precipitates in fine-grained layers. Tensile tests indicate that the sample extruded at 380 ℃ has a superior combination of strength and ductility. This is mainly attributed to the synergy of the heterogeneous texture between coarse and fine-grained layers, hetero-deformation induced strengthening and hardening. The fine-grained layers facilitate the activation of prismatic slips, while coarse-grained layers make it easier to active basal and pyramidalslips, especially for the sample extruded at 380 ℃. The activation of pyramidalslips contributes to coordinating further plastic deformation.