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通过X射线衍射仪、光学显微镜和透射电镜研究Mg-5.51Zn-0.49Zr镁合金在热压缩实验中动态再结晶的位错机制。结果表明,当应变速率为1×10~(-3) s~(-1)时,由于位错攀移沿单一方向滑动,合金出现连续动态再结晶;当热压缩温度达到350°C、应变速率为1×10~(-2) s~(-1)时,由于位错发生滑移和攀移,合金出现连续动态再结晶;当热压缩温度达到400°C时,由于亚晶界弓出,合金出现不连续动态再结晶;当应变速率为1×100 s~(-1)时,合金出现连续动态再结晶是由于先导位错在堆积前发生攀移,导致位错在堆积过程中重新排列,形成位错差。一般来说,当应变速率增加时,位错攀移的主要影响机制由空位迁移转变为堆积前先导位错的压应力作用。
The dislocation mechanism of the dynamic recrystallization of Mg-5.51Zn-0.49Zr magnesium alloy during hot compression test was investigated by X-ray diffraction, optical microscopy and transmission electron microscopy. The results show that when the strain rate is 1 × 10 -3 s -1, the alloy undergoes continuous dynamic recrystallization due to the sliding of dislocation climbing in one direction. When the hot compression temperature reaches 350 ° C, the strain At a rate of 1 × 10 ~ (-2) s ~ (-1), continuous dynamic recrystallization occurs due to slip and climb of the dislocations. When the hot compression temperature reaches 400 ° C, When the strain rate is 1 × 100 s ~ (-1), the continuous dynamic recrystallization of the alloy occurs because the lead dislocation collides before stacking, resulting in the dislocation in the accumulation process Rearrange to form a dislocation. Generally speaking, as the strain rate increases, the main influence mechanism of dislocation climbing shifts from vacancy migration to the compressive stress of the leading dislocation before accumulation.