混合稀土对AlMg5Si1铝合金铸态组织与性能的影响

Effect of Rare Earth Elements on Microstructure and Properties of As-Cast Al Mg5Si1 Alloy

通过SEM、EDS和XRD研究了不同质量分数的混合稀土对Al Mg5Si1合金组织与性能的影响。结果表明,稀土可以有效地细化合金晶粒组织,并且提高合金的强韧性。稀土含量为0.7%时合金的抗拉强度最高为194.8 MPa,伸长率为3.3%,比未加稀土的合金抗拉强度和伸长率分别提高了33.0%和153.8%。试验分析还表明,在RE含量低于0.7%时,RE晶粒细化对合金的强韧化的作用能足以抵消针状的不规则多边形Mg2Si对基体的割裂作用。

The effect of rare earth （RE） elements on microstmcture and properties of as-cast A1Mg5Sil alloy was investigated. The microstructure of the A1Mg5Sil alloy with and without the RE addition was characterized by means ofSEM, EDS and XRD. The microstructure analyses revealed that the RE addition refined effectively the grain structure and improved the strength and toughness of the alloy largely. The results of the tensile testing showed that, when the RE content was 0.7 wt.%, the tensile strength of the AlMg5Sil alloy was 194.8 MPa, the elongation was 3.3%, which were 33% and 153.8% respectively higher than the alloy without the RE addition. The experimental observation indicated that, when the RE content was less than 0.7 wt.%, the RE effect on the strengthening and toughening, the grain refinement of the alloy was strong enough to offset the fragmentation effect of Mg2Si with the shape of needle and irregular polygon on the matrix.