Microstructure And Properties Of Half-heusler Alloy/Cu Joint

Half-Heusler alloy is widely used in thermoelectric materials at high temperature because of its good stability,mechanical properties and excellent thermoelectric properties.At present,the ZT value of P type Half-Heusler material is up to 0.9,and the ZT value of N type Half-Heusler material is up to 1.0.Therefore,the establishment of reliable module preparative technique is of great significance to promote the wide application of Half-Heusler alloy.This paper based on the characteristics of Half-Heusler alloy,Ag72Cu28(at.%)solder brazing,the influence and mechanism of brazing temperature and holding time on the Half-Heusler /Cu alloy electrode joint interface structure,shear strength and contact resistance.The main conclusions are as follows:the brazing temperature and holding time have an obvious influence on the interface of P and N Half-Heusler alloy /Cu joints.With the increasing of brazing temperature and holding time,and P and N type Half-Heusler solder alloy interface change from clear to fuzzy,the weld width increasedwhen increasing with the increase of brazing temperature and holding time,the shear strength of P and N type Half-Heusler alloy /Cu joint is increased first and then decreased,the brazing temperature 870℃,holding time 20 min shear strength up to117 MPa,P type of brazing temperature,holding time of up to 20 min 58 MPa.with the increase of brazing temperature and holding time,P and N type contact resistivity Half-Heusler alloy /Cu joints are increased firstly and then decreased,830℃N type brazing temperature,holding time 20 min 3.08 μ?·cm~2 P type brazing temperature,holding time 20 min minimum 1.6 μ?·cm~2.the optimum brazing process is optimized was based on the principle of ensuring sufficient shear strength and low contact resistance,which is brazing temperature 830℃and holding time 20 min.4 pairs of P and N type Half-Heusler thermoelectric modules.