介质电导率对直流电压降法测试腐蚀疲劳裂纹长度准确性的影响

Influence of Medium Conductivity on Accuracy of Measuring Fatigue Crack Length by DCPD Method

研究了高含量NaCl水溶液环境对直流电压降(DCPD)法测试腐蚀疲劳裂纹长度准确性的影响。结果表明:在同一裂纹长度下,随着溶液中NaCl含量的增加,DCPD法测得的电压降出现少量下降;不同NaCl含量溶液中拾取的DCPD信号变化均在±0.2%以内;溶质含量增加使得测得的裂纹长度与实际裂纹长度之间的差异增大,但是均在允许误差范围以内;与纯水相比,质量分数为0.5%的NaCl溶液加速了哈氏C-276合金的疲劳裂纹扩展速率约1.5倍,继续提高溶质含量对于促进疲劳裂纹扩展的效果不再显著。

The effects of high content NaCl solution environment on the accuracy of measuring fatigue crack length by direct current potential drop（DCPD）method were studied.The results show that under the same crack length,the potential drop decreased slightly with the increase of NaCl content in the solution.The DCPD signal obtained in different solutions changed within±0.2%.Higher NaCl content resulted in larger deviation between the tested crack length and the actual crack length.But all the deviations were within the allowed error range.Fatigue crack growth rate of the Hastelloy C-276 alloy in 0.5%NaCl solution increased by 1.5times compared to that in pure water,but the crack growth rate changed slowly with the further increase of NaCl content in the solution.