电梯安全钳用Cu-1.9Be-0.25Co合金高温拉伸行为研究

High Temperature Tensile Behavior of Cu-1.9Be-0.25Co Alloy for Elevator Safety Gear

对780℃×4 h固溶+320℃×8 h时效处理后的电梯安全钳用Cu-1.9Be-0.25Co合金进行高温拉伸试验,获得了不同试验条件下合金的应力-应变曲线和力学性能,并通过光学显微镜、扫描电镜观察其微观组织和拉伸断口形貌。结果表明,温度对时效态Cu-1.9Be-0.25Co合金高温条件下的抗拉强度和伸长率影响显著。随着拉伸温度升高,合金的抗拉强度从262 MPa逐渐下降到24.5 MPa,伸长率和断面收缩率先升高后降低,在730℃时均达到最大值,分别为129.5%和99%,断面收缩率最大值持续到780℃发生下降;合金的断裂机制为:500℃的沿晶脆性断裂+局部韧性断裂的混合断裂机制向600、730、780、830℃条件下韧性断裂转变。

The high-temperature tensile tests were conducted on elevator safety Gear with Cu-1.9 Be-0.25 Co alloy after 780 ℃×4 h solid solution+320 ℃×8 h aging treatment.The stress-strain curve and the change rule of mechanical properties of alloy under different testing conditions were obtained,and the microstructure and tensile fracture morphology of the alloy were observed through optical microscope and scanning electron microscope.The results reveal that temperature has a significant effect on the tensile strength and elongation of the aged Cu-1.9 Be-0.25 Co alloy under high temperature conditions.As the tensile temperature increases,tensile strength of the alloy is gradually decreased from 262 MPa to 24.5 MPa,and the elongation and reduction of area are firstly increased and then decreased,which reach the maximum of 129.5% and 99% at 730 ℃,respectively,and the maximum reduction of area continues to decline until 780 ℃.The fracture mechanism of the alloy is transformed from the composite fracture mechanism of intergranular brittle fracture+local ductile fracture at 500 ℃ to ductile fracture at 600 ℃,730 ℃,780 ℃ and 830 ℃.