介绍一种机械振动细化凝固组织的工艺，振动能量由振动头直接导入熔体，该振动头在振动过程中熔化。研究振动加速度和质量比对 Al-5%Cu 合金微观组织的影响。结果表明：该机械振动可实现熔体内部冷却，冷却速度取决于振动加速度；若在振动过程中，熔体的温度保持在液相线温度以上，该机械振动很难实现晶粒细化；若在凝固初期阶段施加机械振动，凝固组织可以被有效细化。另外，探讨了在机械振动条件下，凝固组织细化的基本机理。%A mechanical vibration technique to refine solidified microstructure was reported. Vibration energy was directly introduced into a molten alloy by a vibrating horn, and the vibrating horn was melted during vibration. Effects of vibration acceleration and mass ratio on the microstructure of Al-5%Cu alloy were investigated. Results show that the present mechanical vibration could provide localized cooling by extracting heat from the interior of molten alloy, and the cooling rate is strongly dependent on vibration acceleration. It is difficult to refine the solidified microstructure when the treated alloy keeps full liquid state within the entire vibrating duration. Significantly refined microstructure was obtained by applying mechanical vibration during the initial stage of solidification. Moreover, mechanisms of grain refinement were discussed.
展开▼
