LY12CZ铝合金疲劳试验热耗散能研究

Research on Heat Dissipation in Fatigue Test of Aluminum Alloy LY12CZ

基于热力学第一定律,以试样瞬时冷却速率为参量,建立了一个单个循环单位体积材料的热耗散能模型。利用红外热像仪对LY12CZ铝合金试样疲劳过程进行非接触式连续测量,研究结果表明:LY12CZ硬铝合金试样表面温度的变化历经明显上升、相对稳定、迅速上升至断裂3个阶段;循环稳定阶段试样表面温度出现波动,波动幅值随应力幅的增加而增大;单位体积材料单个循环的热耗散能随应力幅的增加而增大。

Based on the first law of thermodynamics, a theoretical model is developed in order to calculate the thermal energy dissipated per unit volume and per cycle, in which the cooling rate of the specimen is a parameter obtained from the test. According to the continuous noncontact measurement during the fatigue test of LY12CZ aluminum alloy by using infrared thermography, the surface temperature of material increases at the beginning of the test, then tends to a stationary value and rapidly increases till fracture finally. The surface temperature oscillates around the stationary value with small amplitude which increases with the increase of stress amplitude. The higher the stress amplitude applies, the higher the thermal energy dissipates per unit volume and per cycle.