腐蚀疲劳波形效应的裂尖析氢、输氢模型与试验验证

把裂尖表面形变动力学和裂尖表面氢反应电化学动力学相结合，对裂尖表面析氢反应的波形效应进行了定量分析，把裂尖形变动力学与位错运动力学相结合，提出了氢的接力式位错输送概念，并建立了波形效应的位错输氢模型，用上述定量模型与理论对正据齿波、三角波和负锯齿波三种波形的腐蚀疲劳裂纹扩展速率的相对大小进行了预测。为验证上述模型，还用疲劳测试和断口分析和研究了三种波形对GC－4（40CrMnSiMoVA)钢在3．5％NaCI溶液中的腐蚀疲劳裂纹扩展特性的影响。试验结果与模型预测结果十分吻合。

A MODEL OF HYDROGEN EVOLUTION AND TRANSPORT AT CRACK TIP FOR DESCRIBING THE EFFECT OF WAVEFORM ON CORROSION FATIGUE AND THE EXPERIMENTAL VERIFICATION THEREOF

A quantitative analysis based on comprehensive kinetic consideration of deformation and electro chemical hydrogen evolution reaction on crack tip surface was carried out for the effect of waveform on hydrogen evolution reaction.A new concept was proposed of dislocation transport of hydrogen atom in metal matrix interior at the crack tip.On the basis of this concept,a quantitative model was developed of the effect of waveform on hydrogen dislocation transport process.Then the relative magnitude of corrosion fatigue craCk growth rate was calculated and compared with for the three waveforms including triangle(TR), positive sawtooth(PS),and negative sawtooth(NS).Finally,experimental studies were conducted with these three waveforms for GC-4(40CrMnSiMoVA) steel in 3.5% NaCl solution by measurement of macroscopic fatigue behaviour and by observation of microscopic fracture features.It was concluded thatthe test results are in very good agreement with the predicted results.