含Sc的6005A铝合金的微观组织与拉伸性能

Microstructures and Tensile Properties of 6005A Alloy Containing Trace Sc

摘要:

6005A铝合金广泛应用于轨道交通和汽车等领域中，通过添加微量元素可进一步提高其强度和塑性。采用铸锭冶金法制备出直径为258 mm含Sc 的6005A铝合金铸锭，合金铸锭经均匀化后热挤压成2.5—3 mm的多腔体空心型材，同时研究了微量Sc对6005A铝合金微观组织与拉伸性能的影响，以及不同时效制度下含Sc的6005A合金组织与性能。结果表明：添加微量的Sc到6005A合金中，可提高合金的强度，当Sc质量分数为0.06%时合金的抗拉强度、屈服强度分别提高了14.8%和16.8%；添加微量Sc的合金晶粒得到细化，减少了枝晶偏析，形成了弥散的Al₃Sc相，抑制了合金的再结晶。此外，含Sc的6005A合金经175 °C时效8 h析出了大量弥散分布的细小β"相，其强化效果显著。因此，通过添加Sc元素对6005A合金性能有较大的改善。

Abstract:

In this paper， 6005A aluminum alloy with addition Sc ingots with a diameter of 258 mm were prepared by ingot metallurgy. After homogenization treatment， the alloy ingots were hot extruded into 2.5—3 mm multi-cavity hollow plates. The effects of Sc addition and aging treatments on the microstructures and tensile properties of 6005A aluminium alloy， were systematically investigated. The results showed that the addition of Sc to 6005A alloy could significantly improve the strength of the alloy， and the tensile strength and yield strength of the alloy with 0.06% Sc increased by 14.8% and 16.8%， respectively. Besides， the addition of Sc could refine the alloy grain， reduce dendrite segregation， and form a diffuse Al₃Sc phase to inhibit recrystallisation process. The 6005A alloy containing Sc precipitated numerous uniformly distributed fine β" phases after aging treatment at 175 °C for 8 h， which had the best strengthening effect. Thus， adding Sc to 6005A aluminum alloy is beneficial for improving its mechanical properties.