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 ??·cm~2 P type brazing temperature,holding time 20 min minimum 1.6 ??·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.