(1.兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室，兰州 730050；
2.兰州理工大学有色金属合金及加工教育部重点实验室，兰州 730050)
摘 要: 以AlSi10MnMg铝硅合金为基础，研究微量Sr+Ce复合变质对AlSi10MnMg合金显微组织、导热性能及力学性能的影响。结果表明：在金属型铸造条件下，Sr、Ce的添加有效改善了AlSi10MnMg合金中共晶Si形貌，降低了Si相尺寸，提高了Si相圆整度，进而提升了合金导热率及力学性能。添加0.05%Sr+0.02%Ce (质量分数)时合金变质效果最优，与未变质的AlSi10MnMg合金相比，其导热率提升了14.86%，达到181.68W/(m·K)；抗拉强度提升了42.4%，达到228.94MPa；伸长率提升了101.5%，达到14.62%，实现了导热性能与力学性能的良好结合。而当稀土元素Ce添加量超过0.04%(质量分数)后，合金的导热率及力学性能呈降低趋势。针对复合变质后合金中可能出现的金属间化合物进行建模、优化，并采用第一性原理和Cahill模型对其导热率进行计算，研究发现Sr+Ce复合变质后，合金中出现的Sr-RE金属间化合物会降低AlSi10MnMg合金的导热性及力学性能。
关键字: AlSi10MnMg铝合金；Sr+Ce复合变质；导热率；力学性能；第一性原理
（1.State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology, Lanzhou 730050, China;
2. Key Laboratory of Non-ferrous Metal Alloys and Processing, Ministry of Education,Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:Based on AlSi10MnMg Al-Si alloy, the effects of Sr+Ce compound modification on microstructure, thermal conductivity and mechanical properties of AlSi10MnMg alloy were studied. The results show that the addition of Sr and Ce can effectively improve the morphology and decrease the size and roundness of eutectic Si, and improve the thermal conductivity and mechanical properties of AlSi10MnMg alloy. Compared with the unmodified AlSi10MnMg alloy, the thermal conductivity of the alloy increases by 14.86% to 181.68W/(m·K), the tensile strength increases by 42.4% to 228.94 MPa, and the elongation increases by 101.5% to 14.62%, the combination of thermal conductivity and mechanical properties is realized. However, when the rare-earth element Ce exceeds 0.04% (mass fraction), the thermal conductivity and Mechanical properties of the alloy decrease. Based on the modeling and optimization of the intermetallic compounds that may appear in the alloy after the composite modification, the first-principles and Cahill model are used to calculate the thermal conductivity. It is found that the Sr-RE intermetallic compounds in the alloy after the Sr+Ce composite modification can reduce the thermal conductivity and mechanical properties of AlSi10MnMg alloy.
Key words: AlSi10MnMg aluminum alloy; Sr+Ce compound modification; thermal conductivity; mechanical property; first-principle
