交变载荷下化学镀Ni-P合金在45钢疲劳裂纹尖端的沉积行为研究

Infiltration and Deposition of Electroless Planting Ni-P Deposits at Fatigue Crack Tip of 45 Steels Under Alternate Loads

研究了在交变载荷作用下,化学镀液渗注到裂纹尖端的沉积行为对裂纹扩展速率的影响。用扫描电镜观察了化学沉积处理后裂纹面的形貌,并用能谱仪和X射线衍射仪对裂纹尖端镀层进行了成分和物相分析,最后将未处理试样与化学沉积处理过试样的裂纹扩展速率进行对比。结果表明:裂纹尖端发生了明显的镍磷合金的沉积行为,且在裂纹尖端进行化学沉积处理能有效降低裂纹扩展的速率。

The infiltration and deposition behavior of electroless planting Ni-P deposits at the fatigue crack tip of 45 steels under alternate loads was investigated firstly.The influence of the electroless planting Ni-P deposits on the crack propagation rates was analysed.The morphology and compositions of the chemical deposition were charactered by SEM,EDS and XRD,respectively.The crack growth rates of the samples with and without chemical deposition were compared.The results indicate that the deposition behavior of electroless planting Ni-P alloy obviously occurres at the fatigue crack tip,which effectively reduces the crack growth rates.