疲劳寿命计电阻变化机理的研究

 用退火去除电阻累计的方法，研究了3种交变应变量下疲劳寿命计电阻增加的机理，并对液氮处理和冷作变形后的性能进行了研究。实验结果表明：疲劳寿命计电阻增加的主要贡献来自基体原子排序的改变，而在较低应变水平下，位错和点缺陷是电阻增加的主要原因。冷作变形提高反向应变电阻值，低温下疲劳寿命计性能没有改变。

STUDY ON MECHANISM OF RESISTANCE CHANGE OF FATIGUE LIFE GAGE

The fatigue life gage resistance accumulation will be partly recovered when it is annealed. The experiment result reveals that the resistance change caused by dislocation and point defect will be reserved when it is annealed below temperature of recrystallization, while the resistance change caused by alloy element order in lattice disappeared. Its mechanism of resistance accumulation studied using annealing technique on three alternating strain levels after fatiguing. Its character after treatment in nitrogen and cold work also researched. The experiment results indicated that most resistance accumulation disappeared for low cyclic fatigue after being annealed in temperature about 450℃, and relatively more resistance accumulation was reserved for high cyclic fatigue annealed in this temperature. This shows that the resistance increase due to dislocation and point defect is the main factor, and the prime contribution to resistance increase of fatigue life gage is due to the change of alloy element order in lattice. The resistance is increased in reversed strain after cold work and its character has no distinct change when it keeps in low temperature.