Al-Cu-Mn-Ti系耐热铸造合金高温蠕变性能研究

High Temperature Creep Properties of Al-Cu-Mn-Ti Series Heat-resistant Casting Alloy

为探究新型耐热铸造铝合金Al-Cu-Mn-Ti的高温蠕变性能并探明合金有效热强化相,采用扫描电镜、EDS能谱分析、JMat-Pro材料仿真软件及蠕变持久性能测试等分析手段,对合金试样的显微组织、断口形貌和蠕变应变抗力进行了分析。结果表明,Al-Cu-Mn-Ti合金在250℃服役时合金中有效耐热相以θ′相为主,θ相、T相为辅,300℃时合金有效耐热相以T相、θ相为主;合金在300℃、100 MPa服役条件下测试,持久时间不超过40 h,且断裂方式呈塑性和脆性断裂同时发生;合金在250℃的蠕变强度极限达到了120 MPa,在300℃的蠕变强度极限达到了80 MPa。

In order to investigate the creep properties of a novel heat-resistant casting Al-Cu-Mn-Ti alloy at elevated temperature and determine the effective thermal strengthening phase in the alloy, the microstructure, fracture morphology and creep strain resistance of the alloy specimens were analyzed by SEM、EDS、JMAT-Pro and creep endurance test. The results indicate that the effective heat resistant phases of Al-Cu-Mn-Ti alloy are dominated by θ′ phase, supplemented by θ and T phase at 250 ℃, while those are dominated by T and θ phase at 300 ℃. After testing under the service condition of 300 ℃ and 100 MPa, duration is less than 40 h, and the fracture mode is characterized by plastic and brittle fracture simultaneously. The creep strength limit of the alloy reaches 120 MPa at 250 ℃ and 80 MPa at 300 ℃.