(華南理工大學 機械與汽車工程學院，廣州 510640)
摘 要: 采用拉伸力學性能測試、宏觀腐蝕、掃描電鏡(SEM)、透射電鏡(TEM)等，研究不同Zr含量對擠壓鑄造Al-5.0Cu-0.4Mn合金顯微組織和力學性能的影響，并與重力鑄造的合金的顯微組織和力學性能進行對比分析。結果表明：針對鑄態(tài)合金，無論是擠壓鑄造還是重力鑄造，在Zr含量(質量分數)為0.25%時，合金獲得最佳的抗拉強度、屈服強度和伸長率；而對于熱處理態(tài)合金，當Zr含量從0增加到0.35%時，合金的抗拉強度和屈服強度都隨著Zr含量的增加而增加，但伸長率在Zr含量為0.15%時達到最大值。擠壓鑄造可以顯著改善不同Zr含量合金的伸長率，但對鑄態(tài)合金伸長率的提升幅度明顯優(yōu)于熱處理態(tài)合金的。Zr在鑄態(tài)合金中的強化作用主要是細晶強化，而合金經T6熱處理后，固溶強化以及Al3Zr粒子和θ?相的彌散強化是主要強化機制，擠壓鑄造可以顯著改善Al3Zr粒子的彌散強化效果。
關鍵字: Al-Cu-Mn合金；擠壓鑄造；力學性能；顯微組織
（School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:The effect of Zr on the microstructures and mechanical properties of Al-5.0Cu-0.4Mn alloy prepared by squeeze casting was studied by tensile test, macro corrosion test, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and took comparative analysis with the gravity cast alloy. The results show that the best tensile strength, yield strength and elongation are obtained for both the squeeze cast and gravity cast alloys in as-cast state when the Zr content is 0.25% (mass fraction). As for the heat-treated alloys, the tensile strength and yield strength increase when Zr content increases from 0 to 0.35%. However, the elongation reaches the maximum value when Zr content is 0.15%. Squeeze casting can significantly improve the elongation of the alloys with different Zr contents, but the improvement of the elongation of the as-cast alloys is significantly better than that of the heat-treated alloys. The dominant strengthening mechanism of Zr in the as-cast alloy is the grain refinement. However, the solid solution strengthening and dispersive strengthening of Al3Zr particles and q? phase are the main strengthening mechanisms in the alloy after T6 heat treatment. Squeeze casting can significantly improve the dispersion strengthening effect of Al3Zr particles.
Key words: Al-Cu-Mn alloy; squeeze casting; mechanical property; microstructure
