藉由微結構觀察、DSC(Differential Scanning Calorimetry)量測與 端面淬火測試(Jominy End Quench Test)等，探討微量Zr 與冷加工對 Al4.7Zn1.6Mg 合金淬火敏感性之影響。結果顯示，Zr 元素可有效 抑制淬火敏感性的上升；冷加工則使Al4.6Zn1.6Mg(0.1Zr)合金 淬火敏感性上升。Al4.6Zn1.6Mg0.1Zr 合金經過冷加工後，因再 結晶驅動力較大，新晶粒中的Al3Zr 相失去整合性成為一異質成核 點，故淬火敏感性較熱加工之Al4.7Zn1.6Mg0.1Zr 合金大。長時 間的固溶處理對熱加工之Al4.7Zn1.6Mg 合金無較大影響，然而可 使冷加工之Al4.7Zn1.6Mg 合金的晶粒成長，減少晶界，使其淬火 敏感性稍微下降；長時間固溶處理使Al4.7Zn1.6Mg0.1Zr 合金之 再結晶比例增加，穩定態相異質析出量上升，然熱加工之 Al4.7Zn1.6Mg0.1Zr 合金的穩定態相異質析出量對端面淬火試 驗空冷端之硬度值影響較不明顯，冷加工之Al4.7Zn1.6Mg0.1Zr 合金的穩定態相異質析出量對端面淬火試驗空冷端之硬度值影響較 大。;We investigate the effect of minor Zr and cold working on quenching sensitivity of Al4.7Zn1.6Mg alloy by microstructure observing, DSC measurement and Jominy End Quench Test, and so on. The result shows that Zr element can inhibit quenching sensitivity significantly, while cold working make quenching sensitivity of Al4.6Zn1.6Mg(0.1Zr) obviously. Recrystallization motivation of cold worked Al4.6Zn1.6Mg0.1Zr alloy is larger than hot extruded one and there are many low coherency Al3Zr particles as heterogeneous nucleation sites in the new grains, so the quenching sensitivity of cold worked alloy is more than hot worked one. Longterm solution treatment has no certain impact on hot worked Al4.6Zn1.6Mg alloy, but make average grain size of cold worked Al4.6Zn1.6Mg alloy growth, reduce the grain boundary area and lower quenching sensitivity of cold worked Al4.6Zn1.6Mg alloy slightly. Longterm solution treatment enhance recrystallization fraction of Al4.6Zn1.6Mg0.1Zr alloy, and increase the amount of precipitation of stable phase. The amount of precipitation of stable phase influence hardness ineffectively in the air cooling end of Jominy End Quench test tube of hot worked Al4.6Zn1.6Mg0.1Zr alloy, but effectively for cold worked Al4.6Zn1.6Mg0.1Zr alloy.
