Cu添加剂对Ag-SnO_(2)触点材料界面增强机理的数值模拟

Numerical investigation on interface enhancement mechanism of Ag-SnO_(2) contact materials with Cu additive

Ag-SnO_(2)触点材料的电接触和力学性能常采用添加剂(特别是铜及其氧化物)来改善。为揭示金属添加剂的改善机制,采用实验和数值模拟相结合的方法研究了Cu纳米颗粒对Ag-SnO_(2)触点材料的界面强度和失效行为的影响。建立了有/无Cu纳米颗粒的Ag-SnO_(2)材料的三维代表性体积元(RVE)模型,通过内聚力模型模拟了界面脱粘过程。结果表明,模拟获得的应力−应变曲线和破坏模式与实验结果吻合良好;通过反推法预测得到Ag/SnO_(2)和Ag/Cu界面的强度分别为100和450 MPa。研究发现,SnO_(2)相周围的应力集中是引起界面脱粘的主要原因,从而导致Ag-SnO_(2)触点材料失效;Cu颗粒的加入不仅提高了界面强度,而且有效抑制了裂纹的萌生和扩展。研究结果对提高银基触点材料的加工性能具有参考价值。

The electrical contact and mechanical performances of Ag-SnO_(2) contact materials are often improved by additives,especially Cu and its oxides.To reveal the improvement mechanism of metal additive,the effects of Cu nanoparticles on the interface strength and failure behavior of the Ag-SnO_(2) contact materials are investigated by numerical simulations and experiments.Three-dimensional representative volume element(RVE)models for the Ag-SnO_(2) materials without and with Cu nanoparticles are established,and the cohesive zone model is used to simulate the interface debonding process.The results show that the stress−strain relationships and failure modes predicted by the simulation agree well with the experimental ones.The adhesion strengths of the Ag/SnO_(2) and Ag/Cu interfaces are respectively predicted to be 100 and 450 MPa through the inverse method.It is found that the stress concentration around the SnO_(2) phase is the primary reason for the interface debonding,which leads to the failure of Ag-SnO_(2) contact material.The addition of Cu particles not only improves the interface strength,but also effectively suppresses the initiation and propagation of cracks.The results have an reference value for improving the processability of Ag based contact materials.