微动对LY12CZ铝合金材料疲劳寿命的影响

选用航空铝合金材料LY12CZ为研究对象,以试验为基础,研究了微动对其疲劳寿命的影响.结果表明:在相同的循环应力下,LY12CZ铝合金的微动疲劳寿命比常规疲劳寿命大大降低,最大降幅达到了55%;对于受微动影响的结构,疲劳裂纹形成阶段时间非常短,其寿命只占整个疲劳寿命的15%～20%;微动疲劳裂纹扩展寿命随接触压力、参数Q/fP的增加而降低,随压头曲率半径的增加而增加,而扩展寿命与总寿命的比值Np/Nt随接触压力、参数Q/fP的增加而增加,随压头曲率半径的增加而降低,且参数Q/fP对Np/Nt的影响最大,压头曲率半径最小,接触压力介于二者之间.

The Effect of Fretting on Fatigue Lifetime of Aluminum Alloy LY12CZ

The effect of fretting on fatigue lifetime of LY12CZ aluminium alloy is experimentally investigated. The results show that for the same cyclic bulk stress the fretting fatigue lifetime is low and up to 45% of the normal fatigue lifetime. For the structure suffered by fretting, the time for the initiation of fatigue crack is very short and is only 15% to 20 % of the whole fatigue lifetime. The propagation lifetime of fretting fatigue crack decreases as the normal load and the ratio Q/fP increase, but increase as the pad curvature radius increases. While the ratio N_p/N_t increases as normal load and the ratio Q/fP increase, and decreases as the pad curvature radius increases. Of these parameters, the ratio Q/fP hadve the most pronouced effect on N_p/N_t, followed by the normal load P. The pad curvature radius has the least effect on N_p/N_t.