Studies on the detrimental effect of liquid metal embrittlement cracks on resistant spot weld joint strength have shown conflicting results. To help understand the cause of these discrepancies, this study will investigate the effect of liquid metal embrittlement cracks on weld strength under different hardness ratios between fusion zone and base metal. In this study, a novel methodology using finite element modelling and experimental testing reveals that the liquid metal embrittlement crack affects the weld strength differently under different weld’s hardness ratio, i.e. under low hardness ratio, the cracks have a relatively big effect on weld strength while under high hardness ratio the cracks have relatively little effect. This work helps further understand when LME cracks are detrimental to strength.

中文翻译：

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焊缝硬度比和液态金属脆化裂纹对耐点焊强度的不利影响

关于液态金属脆化裂纹对耐点焊接头强度的不利影响的研究显示出相互矛盾的结果。为了帮助理解这些差异的原因，本研究将研究在熔合区和母材之间的不同硬度比下，液态金属脆性裂纹对焊缝强度的影响。在本研究中，采用有限元建模和实验测试的新方法表明，液态金属脆化裂纹在不同焊缝硬度比下对焊缝强度的影响不同，即在低硬度比下，裂纹对焊缝强度的影响相对较大，而在低硬度比下，裂纹对焊缝强度的影响较大。高硬度比对裂纹的影响相对较小。这项工作有助于进一步了解 LME 裂纹何时对强度有害。