Cu-Sn体系LTTLP连接接头强度与断口分析

Study on shear strength and fracture behavior of Cu-Sn system low-temperature TLP bonded joint

文中通过研究连接时间和连接温度对Cu/Sn/Cu体系LTTLP连接接头力学性能的影响规律及观察接头断口形貌,分析了接头组织对其断裂过程的影响机制.结果表明,连接温度为300℃时,随着连接时间的增加,接头抗剪强度先增加后保持不变,由连接15 min时的16.9 MPa增高至连接120 min后的超过30 MPa;Cu_3Sn型接头的力学性能最优,且残留少量Cu_6Sn_5晶粒时亦不会降低其接头强度;从Sn型接头至Cu_3Sn型接头的转变,接头断裂模式由韧性断裂逐渐过渡到脆性断裂.连接温度从260℃升高至350℃,对Cu3Sn型接头的抗剪强度影响不大,始终保持在30 MPa以上,接头断裂模式均为解理断裂.

In this paper,the effects of bonding time and temperatures on the microstructures and mechanical properties of Cu/Sn/Cu sandwich low-temperature TLP bonded joint were investigated.The shear strength of the 300 ℃ bonded sample was firstly increased and then kept around higher than 30 MPa with the increase of bonding time from 15 min to 150 min,namely,with the strength increased from 16.9 MPa of 15 min to 32.4 MPa of 120 min,and then being remained higher than 30 MPa of 150 min.The Cu_3Sn-type joint possessed the highest mechanical properties,even a few Cu_6Sn_5 particles still remained between two different Cu_3Sn layers.With the TLP joint changing from the pure Sn type to the Cu_3Sn type,the fracture mode was gradually turned from ductile facture to brittle fracture.In addition,with the bonding temperature increasing from 260 ℃ to 350 ℃,the shear strength of Cu_3Sn-type joint was mildly affected,always keeping higher than 30 MPa.All Cu_3Sn-type joints obtained at different temperatures fractured with a mode of cleavage fracture.