Zr含量对BT25合金等温锻件组织及性能的影响

Effect of Zr Content on Microstructure and Properties of Isothermal Forging BT25 Alloy

采用金相显微镜、扫描电镜、X射线能谱仪和力学性能测试等手段,研究了Zr含量对BT25合金等温锻件组织及力学性能的影响。结果表明:采用两相区等温锻造工艺及提高Zr含量可促使BT25合金组织金属流线的形成,抑制了锻后合金冷却时晶界α相的形核及长大,可得到典型的双态组织;随Zr含量增加(由1.65%增加到3.86%),BT25合金在室温,500、550℃高温的拉伸强度和热稳定强度分别提高了161、123、96、57 MPa;断裂韧性由68.9 MPa·m^(1/2)提高至85.5 MPa·m^(1/2)。

The effects of Zr content on the microstructure and mechanical properties of isothermal forging BT25 alloy were investigated by metallurgical microscopy, SEM, EDX and mechanical properties tests. The results show that, the formation of metal streamline of BT25 alloy microstucture can be induced by adopting two-phase region isothermal forging process and increasing the content of Zr. Then, the nucleation and growth of of phase in the grain boundary of the alloy can be suppressed after forging cooling, and the typical binary microstructure can be obtained. With the increase of the content of Zr （increasing from 1.65% to 3.86%）, the tensile strength of BT25 alloy at room temperature, 500 ℃, 550 ℃, and the thermal stability increases by 161 MPa, 123 MPa, 96 MPa and 57 MPa, respectively. The fracture toughness of the alloy increases from 68.9MPa.mta to 85.5 MPa.m112.