冲头式挤压铸造ZA合金强韧化机理的探讨

Strengthening and Toughening Mechanism of Punch\|Squeeze Casting for ZA Alloy

冲头式挤压铸造使ＺＡ合金液在型腔内发生强制流动，有利于压力的传递，大大减少了铸件的缩松缺陷，提高了合金的致密度，使组织细化和形态得到改善，从而使ＺＡ合金塑性显著提高。试验结果表明：在冲头式挤压铸造工艺条件下α和β相已经分解，α和β相的分解程度对ＺＡ合金的强度和塑性有直接的影响。β相分解产物的层片间距减小是强度提高的主要原因，α和β相的分解提高了合金的塑韧性。铝含量的增加对ＺＡ合金的常温力学性能影响不大，但能提高其使用工作温度。铜含量的增加使ε相增多，抗拉强度提高。

The flowing of ZA alloy liquid in the model cavity is enforced under the punch squeeze casting favorable for pressure transmission. The porosity defect is remarkably reduced, the soundness increased, the structure is improved, thus the ductility increased obviously. Results show that and phase have been decomposed under the technology of punch squeeze casting. The and phase decomposition influences the strength and the ductility of ZA alloy. The lamellar spacing decreasing of \|phase decomposition product is the main reason for the strength improved. The decomposition of and \|phase also improves the ductility and toughness of the alloy. The increase of aluminium content has little effect on the improvement of mechanical properties at room temperature, but enhances the working temperature of the ZA alloy. With the increase of Cu content the tensile strength is improved, but the elongation is reduced because of \|phase increase.\=