Dynamic nano precipitation behavior of as-cast Mg-4Li-4Zn-Y alloy during high temperature compression at 450 ℃ was investigated in this paper. The grains were coarse, interdendritic W-Mg₃Y₂Zn₃ mainly existed at grain boundaries and MgZn₂ mainly existed in grains in the as-cast alloy. After hot deformation at 400 ℃/0.1 s⁻¹ and 450 ℃/0.1 s⁻¹, complete dynamic recrystallization occurred, MgZn₂ was dissolved and Mg₂₄Y₅ appeared. Compared with 400 ℃, the number of second phases was more and grains were finer at 450 ℃. Bulk W-Mg₃Y₂Zn₃ particles were broken and partly dissolved during hot deformation, and Zn and Y atoms diffused from grain boundaries into inner grains. Diffused atoms were aggregated at defects caused by deformation, then nano precipitates with a size of tens of nanometers formed at these places without growth. High-density ultrafine nano precipitates with a size of several nanometers were also found. Grains were refined due to PSN progress promoted by relatively large particles and growth restraint by nano precipitates at grain boundaries. The combined strengthening effect of particle dispersion and grain refinement can significantly improve the mechanical properties. Texture in the alloy was randomized during high temperature deformation as well, which was beneficial to reduce mechanical property anisotropy.

研究了铸态Mg-4Li-4Zn-Y合金在450℃高温压缩过程中的动态纳米沉淀行为。晶粒粗大，铸态合金中的枝晶间W-Mg ₃ Y ₂ Zn ₃主要存在于晶界，MgZn ₂主要存在于晶粒内。经过400℃/ 0.1 s ^-1和450℃/ 0.1 s ^-1的热变形后，发生了完全的动态重结晶，MgZn ₂溶解并出现了Mg ₂₄ Y ₅。与400℃相比，在450℃时，第二相的数量更多，晶粒更细。块状W-Mg ₃ Y ₂ Zn ₃颗粒在热变形过程中破裂并部分溶解，并且Zn和Y原子从晶界扩散到内部晶粒中。扩散的原子聚集在由变形引起的缺陷处，然后在这些位置形成数十纳米大小的纳米沉淀物而没有生长。还发现了具有几纳米大小的高密度超细纳米沉淀物。由于相对较大的颗粒促进了PSN的发展，并且由于晶界处的纳米沉淀物而抑制了生长，因此晶粒得以细化。颗粒分散和晶粒细化的组合强化作用可以显着改善机械性能。合金在高温变形过程中的织构也是随机的，这有利于降低机械性能的各向异性。