Research On Preparation And Properties Of Al-Si-W Alloy For Electronic Packaging

In the electronic packaging materials,Al-70 Si alloy has attracted much attention because of its thermal expansion coefficient that can match the Si or GaAs chip,high thermal conductivity and low density of concern.However,the high Si content will greatly reduce the mechanical properties of materials,so that the preparation and mechanical processing performance is poor,can not be large-scale production.In this paper,the Al-70 Si alloy is replaced by Al-50 Si alloy and Al-60 Si alloy,the mechanical properties of high silicon aluminum alloy are improved by introducing elemental W.In this paper,the effect of W on the properties of Al-Si alloy was studied by using powder metallurgy process.It was found that Al-60Si-20 W alloy could achieve the performance of Al-70 Si alloy.In this paper,the effects of mixing time,cold pressing pressure,Step-by-step hot pressing process,sintering temperature and holding time on the microstructure and properties of powder metallurgy Al-60Si-20 W alloy were studied.In this process,the microstructure of Al-50Si-W alloy and Al-60Si-W alloy were analyzed by OM,SEM,XRD and EDS.The thermophysical properties,mechanical properties and mechanical processing of the composites were studied.The effects of W content on the thermophysical properties and mechanical properties of the composites were investigated.The results show that Al-60Si-20 W alloy can get the alloy with good homogeneity after 4h and 8h at the mixing ratio of 5: 1 and the rotation speed of115r/min,the average tensile strength is 168.06 MPa and 156.10 MPa.Under the condition of cold pressure,the punch pressure of 204 MPa,the lower punch pressure of 300 MPa and the step-by-step hot pressing process,the mechanical properties of Al-60Si-20 W alloy were best at 188.08 MPa after holding for 0.5h at 750 ?.In the Al-Si-W alloy,the thermal expansion coefficient of the material is negatively correlated with the W content.At 50 ~ 150 ?,the CTE value of the Al-60Si-25 W alloy is reduced to 6.75×10-6K-1,the thermal conductivity at room temperature was linearly correlated with W content.Among them,Al-50Si-35 W alloy reaches129W/(m·K),the tensile strength of the material increases with the increase of W content,Al-60Si-20 W alloy reaches 168.6MPa,and all the density of materials are less than 3.6g/cm3.The results show that Al-60Si-20 W alloy can replace Al-70 Si alloy because of its excellent mechanical properties and good thermophysical properties.