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新型镍基粉末高温合金的微观组织和力学性能

Microstructure and mechanical properties of a novel nickel-based powder superalloy

  • 摘要: 以新型镍基粉末高温合金FGH4113A(WZ-A3)为研究对象,采用“真空感应熔炼+氩气雾化制粉+热等静压+热挤压+等温锻造”工艺路线制备全尺寸涡轮盘,系统研究了锻造态FGH4113A合金在不同热处理状态下的微观组织和力学性能。结果表明:FGH4113A合金全尺寸涡轮盘宏观形貌良好,微观晶粒组织细小均匀;经亚固溶热处理后,平均晶粒度ASTM 11~13级,室温和550 ℃的屈服强度分别为1249和1185 MPa,抗拉强度分别为1674和1656 MPa,断后伸长率分别为23.5%和19.5%,在温度700 ℃,应变范围0~0.8%,加载频率0.33 Hz条件下的疲劳寿命均值为35000周次;经过固溶热处理后,平均晶粒度ASTM 6~8级,700和800 ℃的屈服强度分别为1063和966 MPa,抗拉强度分别为1403和1112 MPa,断后伸长率分别为17.5%和12.0%,在温度800 ℃,应力330 MPa,蠕变伸长量0.2%条件下的蠕变寿命均值为384 h,在温度700 ℃,应力强度因子范围30 MPa·m0.5条件下的裂纹扩展速率小于5×10−4 mm·cycle−1

     

    Abstract: A novel nickel-based powder metallurgy superalloy FGH4113A (WZ-A3) was used to manufacture the full-size turbine disks by the process route of “vacuum induction melting + argon atomization + hot isostatic pressing + hot extrusion + isothermal forging”. The microstructure and mechanical properties of the forged FGH4113A alloys under the different heat treatment conditions were systematically studied. The results show that, the full-size turbine disks prepared by FGH4113A alloy have the good macro morphology and homogeneous grain structure. After the subsolvus heat treatment, the average grain size is ASTM 11~13, the yield strength at room temperature and 550 ℃ are 1249 and 1185 MPa, the tensile strength are 1674 and 1656 MPa, and the elongation after fracture are 23.5% and 19.5%, respectively. The mean fatigue life under the conditions of temperature 700 ℃, strain range 0~0.8% and loading frequency 0.33 Hz is 35000 cycles. After the supersolvus heat treatment, the average grain size is ASTM 6~8, the yield strength at 700 ℃ and 800 ℃ are 1063 and 966 MPa, the tensile strength are 1403 and 1112 MPa, and the elongation after fracture are 17.5% and 12.0%, respectively. The mean creep life under the conditions of temperature 800 ℃, stress 330 MPa and creep elongation 0.2% is 384 h. The crack propagation rate under the conditions of temperature 700 ℃ and stress intensity factor range 30 MPa·m0.5 is less than 5×10−4 mm·cycle−1.

     

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