( 1. 哈尔滨工业大学 现代焊接生产技术国家重点实验室，
哈尔滨 150001;
2. 深圳市亿铖达工业有限公司， 深圳 518101)
摘 要: Sn-Ag-Cu系合金是最有可能替代Sn-Pb钎料的无铅钎料。 介绍了一种测量其力学性能的新方法， 即通过微压痕仪精确测量不同加载速率下压子的压入深度h与加载载荷F的关系来确定钎料的弹性模量E和蠕变速率敏感指数m。 结果表明： 加载速率对钎料蠕变压痕F-h曲线和压入深度有着重要的影响； Oliver-Pharr方法确定的钎料弹性模量取决于卸载过程而与加载速率无关。 基于压痕做功概念定义了压痕蠕变硬度和蠕变应变速率， 从而给出钎料的蠕变速率敏感指数。 Sn-3.5Ag-0.75Cu与Sn-3.0Ag-0.5Cu钎料蠕变压痕测试表明合金成分影响Sn-Ag-Cu系无铅钎料的力学性能。
关键字: 无铅钎料； 微压痕； 弹性模量； 蠕变速率敏感指数；Sn-Ag-Cu系
using micro-indentation
（ 1. State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China;
2. Yik Shing Tat Industrial Co., Ltd., Shenzhen 518101, China）
Abstract: Sn-Ag-Cu series alloy is considered as the lead-free alternative to lead-tin alloys. A new method was introduced to measure the mechanical properties, i.e. modulus of elasticity and creep strain rate sensitivity by using depth-sensing micro-indentation with the influence of loading rates on load—displacement (F-h) relationship. The resulting indentation F-h curves are loading-rate-dependent and have varying creep penetration depths during the same hold time. The derived modulus of elasticity values with Oliver-Pharr method from unloading curves are loading rate-independent. The creep strain rate sensitivity can be determined from the relationship between the creep hardness and creep strain rate by the definition of “work of indentation”. Also, micro-indentation tests on two Sn-3.5Ag-0.75Cu and Sn-3.0Ag-0.5Cu lead-free solder alloys show a slight influence of alloy composition on mechanical properties for Sn-Ag-Cu series solder.
Key words: lead-free solder; micro-indentation; modulus of elasticity; creep strain rate sensitivity; Sn-Ag-Cu series
