【摘要】 以部分扩散预合金Fe-2Cu-2Ni-1Mo-1C粉末为原料,利用模壁润滑温压技术与3种烧结工艺制备合金材料,研究不同烧结工艺下合金的疲劳性能。结果表明:3组不同烧结工艺制备的试样在104~109循环周次下的应力幅值-循环周次(S-N)曲线均为一条连续下降的曲线,不存在传统疲劳概念上的疲劳极限,只存在条件疲劳极限;在107循环周次下,3组试样的条件疲劳极限分别为280、264和239 MPa。断口分析发现,3组试样的疲劳裂纹均萌生在试样表面的棱角处,且均表现为多源萌生;疲劳裂纹扩展以穿晶断裂为主,不同的组织对裂纹的扩展有明显的影响;扩展区存在典型的解理和疲劳辉纹形貌;断裂区有塑性韧窝出现。更多还原

【Abstract】 Partially diffused pre-alloy Fe-2Cu-2Ni-1Mo-1C powders materials was selected for fatigue study.Samples were prepared by wall lubricated and warm compaction and subsequent sintering under three different conditions.The focus of the present work is to investigate the effect of sintering condition on fatigue strength.The results show that the stress range value-number of cycle curves(S-N) of all specimen are decreasing continuously with number of cycles increasing.Traditional fatigue limit can’t be observed.Only the conditional fatigue limit exists.Under 107 cycles,the conditional fatigue limit of three group of samples sintered in different processes are 280 MPa,264 MPa and 239 MPa,respectively.Fatigue fracture morphology shows crack initiates from multi-source on surface edge.The crack exhibited typical transcrystalline pattern,and its propagation is obviously affected by microstructure.Cleavage,fatigue striations and ductile dimple fracture are observed.更多还原