中文摘要：

采用电子拉伸实验机、金相显微镜、扫描电镜及透射电镜，研究了单辊搅拌冷却技术（Shearing-Cooling-Rolling，简称SCR）成形Al-3Mg-0．4Sc合金线材的组织与性能。结果表明：经SCR成形的合金线材晶粒组织非常细小，Sc主要以初生Al3Sc粒子和次生Al3Sc粒子存在。初生Al3Sc粒子是在SCR成形中凝固形成的，作为非均质晶核细化合金晶粒。次生Al3Sc粒子是合金在热处理过程中沉淀析出的，有效钉扎位错和亚晶界，抑制合金再结晶。d5．9mm合金线材320℃时效2h的抗拉强度为425MPa，延伸率为19．8％。SCR成形Al-3Mg-0．4Sc合金具有较高强度的主要原因有两个：1）SCR成形单辊剪切细化晶粒和初生Al3Sc粒子作为非均质晶核细化晶粒共同作用所产生的细晶强化；2）适当热处理过程中沉淀析出的细小、弥散的Al3Sc强化相粒子的沉淀强化。

英文摘要：

The mierostrueture and property of Al-3Mg-0.4Sc formed by SCR（Shearing-Cooling-Rolling）technology have been studied by tensile properties measurement, optical microscope, scanning electron microscope （SEM）, transmission electron microscope（TEM） and energy spectrum analysis. The experimental results show that the grain size of Al-3Mg-0.4Sc alloy formed by SCR is very fine, minor Sc exists in the forms of primary Al3Sc and secondary Al3Sc. Primary Al3Sc is formed during solidification in the processing of SCR, it can refine grain size as heterogeneous nucleus. Secondary Al3Sc dispersoids precipitating from the supersaturated α（Al） solid solution in the heating process, it can effectively pin dislocation, subgrain boundary and inhibit recrystallization. The tensile strength of d5.9 mm alloy wire is 425 MPa, elongation is 19.8%. The main two reasons of higher strength are： 1） fine-grained strengthening by combined action of SCR technology and refining grain size of primary Al3Sc as heterogeneous nucleus; 2） precipitation strengthening of secondary Al3Sc during the aging processing.