93WNiCu合金的高温性能及断裂机理研究

Research on High Temperature Properties and Fracture Mechanism of 93WNiCu Alloy

试验选用粉末冶金法制备了93WNiCu合金材料,通过高温拉伸试验、高温线膨胀系数测试,得出材料在700~1300℃的高温力学性能和室温至1300℃的线膨胀系数的变化规律,并研究了温度对93WNiCu合金高温力学性能、线膨胀系数的影响机理。结果表明:93WNiCu合金在常温状态下可以表现出良好的强韧性,但在高温环境下材料的抗拉强度急剧下降,宏观表现为抗拉强度极低,延伸率消失,断裂模式也由微观多种断裂模式转变成强度最低的钨钨界面分离;93WNiCu合金的线膨胀系数随温度的升高而平缓增加,温度的增加降低了钨-粘结相界面强度,使材料的热膨胀对温度越来越敏感;针对93WNiCu合金高温性能不理想的问题,研究从添加微量元素、热处理的角度,给出了提升钨镍铜合金综合性能的建议。

The 93WNiCu alloy materials prepared by powder metallurgy were selected for this project.Through high temperature tensile and thermal linear expansion coefficient tests,the mechanical properties of the material from 700℃to 1300℃and the coefficient of linear thermal expansion from room temperature to 1300℃were obtained,and the influence mechanism of high temperature on mechanical properties and linear expansion coefficient of 93WNiCu alloy was studied.The experimental results demonstrated that the 93WNiCu alloy could exhibit good strength and toughness at room temperature,and yet the significant drop in tensile strength of the material at high temperature is presented as it manifests the low tensile strength,the disappearance of elongation,and the fracture mode changing from microscopic fracture modes to tungsten-tungsten interface separation with the lowest strength.The linear expansion coefficient of 93WNiCu alloy increases gently with the increase of temperature.Indeed,increasing temperature leads to a decrease in the strength of the tungsten-bonded phase interface,which makes the material thermal expansion more sensitive to temperature.Suggestions on improving the comprehensive properties of W-Ni-Cu alloy are given in terms of trace elements addictive and heat treatment.