自然时效对键合银丝拉伸性能的影响

Effect of Natural Aging on Tensile Properties of Silver Bonding Wire

中文关键词: 键合银丝  自然时效  再结晶  拉伸性能  延伸率波动

英文关键词: silver bonding wire  natural aging  recrystallization  tensile property  elongation fluctuation

中文摘要:

      目的 厘清自然时效状态下纯银键合线拉伸性能的演变规律，探索超细丝拉伸性能波动的原因，为高稳定性键合丝的制备提供指导。方法 首先选择同一批次纯银坯料，调控拉拔与中间退火工序，制备不同等效应变的超细丝;其次在常温下对拉拔态超细丝进行时效处理;最后测试不同时效时间下超细丝的拉断力与延伸率，分析其演变规律。结果 拉拔态超细丝的拉断力随自然时效时间的延长而不断减小;应变越高，初始抗拉强度越高，但不同应变的超细丝抗拉强度均逐渐稳定于约180 MPa;延伸率随时效时间的延长而不断增大，但其演变时间曲线的特征节点滞后于拉断力的特征节点;不同应变超细丝初始延伸率的绝对波动较小，在时效后期，绝对波动值呈杂乱波动状态;延伸率相对波动初始较大，当时效0~2 d时，出现相对波动高峰期，高峰期持续1~5 d，后续相对波动会减小。结论 纯银超细丝拉伸性能自然时效演变存在孕育期、快变期、稳定期;延伸率的相对波动存在起始期、高峰期、稳定期;在拉伸性能的快变期、延伸率相对波动的高峰期制备键合丝易导致性能不稳定。

英文摘要:

      The work aims to clarify the evolution law of tensile properties of silver bonding wires under natural aging and explore the reasons for the fluctuation of tensile properties of superfine wires. First, the same batch of pure silver materials were selected to prepare ultrafine wires with different specifications of strain through adjustment of the drawing and intermediate annealing processes. Then, the drawn ultrafine wires were aged at room temperature. Finally, the breaking force and elongation of the ultrafine wires were tested with different aging time, and the evolution law was analyzed. The results showed that the tensile force of the drawn superfine wires decreased with natural aging. The higher the strain, the higher the initial tensile strength. However, the superfine wires with different strains was gradually stable at about 180 MPa. The elongation increased with aging, but the evolution lagged behind the tensile force. The absolute fluctuation of the initial elongation rate of ultrafine wires with different strains was relatively small. In the later stage of aging, the absolute fluctuation showed a disorderly fluctuation. The relative fluctuation of elongation was relatively large at the beginning. After aging for 0-2 d, the peak period of relative fluctuation occurred, and the peak period lasted for 1-5 d. Subsequently, the relative fluctuation would decrease. The natural aging evolution of tensile properties of silver bonding wires has an incubation period, a rapid change period and a stable period, and the relative fluctuation of elongation has an initial period, a peak period and a stable period. The preparation of bonding wires in the rapid change period and the peak period of relative fluctuation of elongation is easy to lead to unstable properties.