新型铝锂合金AA2198高频疲劳红外热耗散演化规律

利用红外成像技术开展新型铝锂合金AA2198高频疲劳（100 Hz）热耗散演化规律研究，发现不同应力条件下疲劳热耗散呈现上下波动特征，试件平均温度随着加载应力的提升有增加的趋势，但升温现象并不明显，不同应力条件下温度变化幅值小于1℃。疲劳试验初期和疲劳断裂时伴随着急剧升温过程，提出的能量转化理论模型合理解释了疲劳热耗散演化过程。研究还发现，喷丸强化在试件表面形成的残余压应力有助于激发疲劳裂纹的闭合效应，对试件的升温过程具有抑制作用。

High-frequency fatigue infrared heat dissipation of new Al-Li alloy AA2198

An infrared imaging technology is used to study the rule of fatigue heat dissipation evolution of a new Al-Li alloy AA2198 under a high-frequency fatigue test condition of 100 Hz. It is found that fatigue heat dissipation on specimens shows fluctuation characteristics under different stress conditions, with its average temperature inclined to increase with the rise of the loading stresses. However, the temperature rise on specimens during fatigue test is not obvious, and the amplitudes of temperature variation under different stress condition is generally smaller than 1℃. The beginning of fatigue test and the moment of fatigue fracture occurrence are accompanied by a rapid temperature rise. An energy conversion theory model is proposed to explain the evolution process of fatigue heat dissipation. Meanwhile, the residual compressive stress formed on specimen subsurface during the shot peening process helps to intensify the fatigue crack closure, inhibiting the temperature rise on specimens.