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用薄片三点弯曲方法,配合声发射技术,对五种材料不同离子氮化工艺的渗层性能进行了测量。分析表明,弯曲时心部首先进入屈服状态,因此,只有开裂时的施力点位移,才能明确表征渗层的塑性。加载时,裂纹首先在化合物层形成,然后向扩散层扩张。利用声发射信号,可以分别对这两个层进行讨论。比较了不同氮化温度、时间及心部强度等对渗层性能的影响,证明在某个氮化温度和时间下存在渗层塑性的最佳值。在最佳工艺条件下,五种材料渗层塑性的优劣顺序是:42CrMo、40Cr、35CrMnSi、20CrMnTi、38CrMoAl。渗层强度和塑性随心部硬度降低而下降。磨去化合物层后,渗层塑性将显著改善。
The lamellar properties of five materials with different ion nitriding processes were measured by three-point bending method and acoustic emission technique. The analysis shows that when bending, the heart first enters the yield state. Therefore, only the displacement of the point of application at the time of cracking can clearly characterize the plasticity of the layer. Upon loading, the crack first forms in the compound layer and then expands to the diffusion layer. Using acoustic emission signals, the two layers can be discussed separately. The effects of different nitriding temperature, time and core strength on the properties of the infiltrated layer were compared. It was proved that there existed the best plasticity of the infiltrated layer under a certain nitriding temperature and time. Under the optimum process conditions, the order of the plasticity of the five materials is: 42CrMo, 40Cr, 35CrMnSi, 20CrMnTi and 38CrMoAl. The strength and ductility of the layer decreases with decreasing hardness of the heart. After milling off the compound layer, the drawdown ductility will be significantly improved.