基于纳米压痕法的富Sn相应力-应变关系的研究

Research on the stress-strain relationship of Sn-rich phase based on nanoindentation

在电子封装领域,无铅钎料主要是二元、三元Sn基共晶或近共晶合金,其基体相为富Sn相。为得到富Sn相的力学性能及应力-应变关系,由纳米压痕试验测试获得了富Sn相的弹性模量与硬度,并得到载荷-位移曲线。采用有限元反演分析的方法确定了富Sn相的特征应力和特征应变,并由量纲函数确定应变强化指数。将特征应力和特征应变强化指数等参数代入幂强化模型,计算得到富Sn相的屈服强度为31.51 MPa,并最终确定富Sn相的应力-应变关系函数表达式。

At present,the lead-free solders used are mainly binary or ternary Sn-based eutectic or near-eutectic alloys in the field of electronic packaging,and the matrix phase is Sn-rich phase.In order to obtain the mechanical properties and stress-strain relation of the Sn-rich phase,the elastic modulus E and the hardness H of the Sn-rich phase were obtained by nanoindentation test,and the load-displacement curve was obtained.Then,the representative stress and representative strain of the Sn-rich phase are determined by the finite element reverse analysis method,and the strain hardening exponent n was determined by the dimensional function.Finally,the above parameters were substituted into the power-law stress-strain behavior model,the yield strength of Sn-rich phase was calculated to be 31.51 MPa,and the expression of stress-strain relation function of Sn-rich phase was finally determined.