固溶工艺对Ni-Cr-Al-Fe合金电学性能及屈服强度的影响

对合金丝材进行了不同温度和时间的固溶处理,探究了固溶参数对晶粒尺寸、电阻率、电阻温度系数及屈服强度的影响规律,对比了固溶态和时效态合金的性能差异。结果表明:提升固溶温度或延长保温时间,均使电阻率升高、电阻温度系数下降,有利于改善合金的电学性能;合金晶界移动激活能为674.25 kJ/mol,晶粒生长动力学方程为:D-^3.3_t=3.80×10³⁰texp-8.11×10⁴T;屈服强度与晶粒尺寸存在关系式:Rp0.2=341.19+354.64D^-0.5_t;通过950 ℃×7.5 min+430 ℃×0.5 h固溶时效处理后,合金的屈服强度为445 MPa,电阻率为132.2 μΩ·cm,电阻温度系数为2.2×10^-6℃^-1,满足制备精密电阻元件的要求。

Effect of solution treatment on electrical properties and yield strength of Ni-Cr-Al-Fe alloy

The effects of solution temperature and time on the grain size, resistivity, TCR and yield strength of the precision resistance alloy wire were examined. Also, the properties of as-quenched and as-aged alloys were compared. The results show that the resistivity increases with the increase of solution temperature and holding time, while the TCR decreases. Both the variations are useful to improve the electrical properties of the alloy. The activation energy of grain boundary migration is 674.25 kJ/mol, and the comprehensive dynamic equation of grain growth is as follow: D-^3.3_t=3.80×10³⁰texp-8.11×10⁴T. The relationship between yield strength and grain size of this alloy is deduced to be Rp0.2=341.19+354.64D^-0.5_t. After solid solution at 950 ℃ for 7.5 min and aging at 430 ℃ for 0.5 h, the yield strength, resistivity and TCR are 445 MPa, 132.2 μΩ·cm and 2.2 × 10^-6℃^-1, respectively. And thus the alloy is suitable to be used as precision resistance component.