(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 在迄今為止的所有微合金化元素中，鈧可最大程度提高鋁合金綜合性能。相比傳統(tǒng)鋁鎂合金，新型Al-Mg-Sc-Zr合金抗拉強(qiáng)度提高60~130 MPa，屈服強(qiáng)度提高80~150 MPa，且可獲得大于2000%高速超塑性。與傳統(tǒng)鋁鋅鎂合金相比，新型Al-Zn-Mg-Sc-Zr合金抗拉強(qiáng)度提高66~96 MPa，屈服強(qiáng)度提高36~98 MPa，鎢極氬弧焊系數(shù)大于0.75，攪拌摩擦焊系數(shù)大于0.90，且可獲得大于1500%高速超塑性。鈧鋯添加到鋁合金中可形成Al3(Sc,Zr)粒子，該粒子可細(xì)化鑄造組織、抑制再結(jié)晶發(fā)生和穩(wěn)定細(xì)晶組織，產(chǎn)生顯著的細(xì)晶強(qiáng)化、亞結(jié)構(gòu)強(qiáng)化和析出強(qiáng)化，從而提高合金強(qiáng)度，實(shí)現(xiàn)優(yōu)良的超塑性能。
關(guān)鍵字: 鋁合金；Al-Mg-Sc-Zr合金；Al-Zn-Mg-Sc-Zr合金; 微合金化；強(qiáng)化機(jī)制；超塑性
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:In all micro-alloying elements, scandium offers the greatest potential for improving the property of aluminum alloys. Sc and Zr can improve the tensile strength and yield strength by 60-130 MPa and 80-150 MPa, respectively. The new Al-Mg-Sc-Zr alloy exhibits high strain rate superplasticity with the elongation more than 2000%. Compared with the tensile strength and yield strength of conventional Al-Zn-Mg, the corresponding values are 66-96 MPa and 36-98 MPa higher, respectively. Moreover, the welding coefficients of tungsten inert gas and friction stir welded joints are 0.75 and 0.90, which are higher in the new Al-Zn-Mg-Sc-Zr alloy, respectively. Furthermore, excellent high-strain superplasticity with the elongation above 1500% can be obtained in the new Al-Zn-Mg-Sc-Zr alloy. The Al3(Sc, Zr) particles can refine casting structure, inhibit recrystallization and the stabilize fine grain structure, and thus cause significant grain refinement strengthening, substructure strengthening and precipitation strengthening, which leads to the improvement of strength and excellent superplasticity.
Key words: aluminum alloy; Al-Mg-Sc-Zr alloy; Al-Zn-Mg-Sc-Zr alloy; micro-alloying; strengthening mechanism; superplasticity
