【摘要】 本文研究一次拉伸型过载对奥氏体不锈钢疲劳裂紋近门槛值扩展的影响.试验结果表明,过载对门槛值的影响和过载比P₀/P_max的大小有关;P₀/P_max>1.4时,门槛值随着过载比增加而线性提高.提出了裂纹扩展速率减缓和门槛值提高的主导原因是过載大大促进裂纹顶端闭合,即塑性诱发闭合和断裂表面粗糙诱发闭合.更多还原

【Abstract】 The effect of single tensile overload on crack propagation near the threshold in an austenite stainless steel has been investigated. The threshold value increases with the increase of overload ratio P_o/P_max as it is larger than 1.4. But the threshold value will not be effected by this ratio while it is less than 1.4. It was supposed that the reduction of crack propagation and increase of the threshold value arise primaryly from crack tip closure,i.e. plasticity-induced and roughness-induced closure.更多还原