(1. 中南大学 轻合金研究院，长沙 410083；
2. 中南大学 材料科学与工程学院，长沙 410083；
3. 中车长春轨道客车股份有限公司，长春 130062)
摘 要: 采用铸锭冶金法制备出不同Sc含量的6005A合金铸锭，合金铸锭经均匀化、热轧、中间退火、冷轧成2.5 mm厚的薄板，研究Sc含量对6005A合金拉伸性能、晶粒大小、金相组织及其相组成的影响。结果表明：微量Sc可提高6005A合金的强度，其中含0.07%Sc的合金具有最佳的拉伸性能，其抗拉强度、屈服强度分别提高19 MPa、47 MPa，伸长率也提高1.2%；添加微量Sc的合金晶粒得到细化，且随着Sc含量的增加，细化效果越明显；添加微量Sc减合金中枝晶的偏析，形成弥散的Al3Sc相，抑制合金的再结晶；随着Sc含量的增加，晶内弥散的Mg2Si相得到细化。
关键字: 6005A合金；Sc；微合金化；Al3Sc相
（1. Research Institute of Light Alloy, Central South University, Changsha 410083, China;
2. College of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. CRRC Changchun Railway Vehicles Co., Ltd., Changchun 130062, China）
Abstract:The 6005A alloy ingots with different Sc contents were prepared by ingot metallurgy (IM). And the alloy ingots were homogenized, hot rolled, intermediate annealed and cold rolled into 2.5 mm thick sheets. The effects of Sc content on the tensile properties, grain size, metallographic structure and phase composition of 6005A alloy were studied. The results show that the strength of 6005A alloy can be improved by trace Sc, and the alloy containing 0.07% Sc has the best tensile properties. The tensile strength and yield strength are increased by 19 MPa and 47 MPa, respectively, and the elongation is also increased by 1.2%. The grain of the alloy with trace Sc is refined, and the refining effect is better with the increase of Sc content. The addition of trace Sc reduces the segregation of dendrite in the alloy, forms dispersed Al3Sc phase, and inhibits the recrystallization of the alloy. With the increase of Sc content, the dispersed Mg2Si phase is refined.
Key words: 6005A alloy; Sc; microalloying; Al3Sc phase
