Research On Diamond/Al Composite Prepared By TIG Melting

Diamond/Al composite has many advantages,such as high thermal conductivity,adjustable coefficient of thermal expansion,low density,isotropic.It is widely used in the field of electronic information technology industry.TIG melting has advantages,such as argon protection,energy concentration,high production efficiency,and so on.Therofore,in this paper,diamond/Al composite was prepared by this method.Combined with OM,SEM,EDS,XRD,thermal conductivity measuring instrument and other analysis methods,researched the influence of arc current,diamond volume fraction and the composition of aluminum matrix on the microstructure and property of diamond/Al composite.The results showed that,the diamond/Al samples were prepared by this experiment,diamond distributed uniformly in the aluminum matrix.With the arc current increased,aluminum matrix becomed dense,the interface between diamond and aluminum matrix becomed better,holes and interface cracks in the samples were decreased,the relative density and thermal conductivity of the samples increased.With the diamond volume fraction increased,holes and interface cracks in the samples were increased.Compared with volume fraction 50% diamond/Al samples of the same arc current and the same aluminum matrix,the volume fraction 25%diamond/Al samples were better.The addition of alloy elements Ti and Si in the aluminum matrix improved the wettability between diamond and aluminum matrix,the interface between diamond and aluminum matrix becomed better,holes and interface cracks in the samples were decreased,the relative density and thermal conductivity of the samples increased.Compared with the same arc current,the same volume fraction diamond/Al-2%Ti samples,the relative density of diamond/Al-5%Ti samples increased,the effect of adding 5%Ti into the aluminum matrix to improve the wettability between diamond and aluminum matrix was better than adding 2%Ti,but the thermal conductivity decreased,too many Ti increased the precipitation of second phase,the thermal conductivity of aluminum matrix was reduced,then affected the thermal conductivityof the sample.Compared with the same arc current,the same volume fraction diamond/Al-2%Ti,diamond/Al-5%Ti samples,the relative density and thermal conductivity of diamond/Al-12%Si samples were decreased,the result showed that the effect of adding 12%Si into the aluminum matrix to improve the wettability between diamond and aluminum matrix,and improve the thermal conductivity of the sample was not better than adding 2%Ti,5%Ti.Compared with the same arc current,the same volume fraction diamond/Al-2%Ti,diamond/Al-12%Si samples,the relative density of diamond/Al-12%Si-2%Ti samples were the best,Ti,Si compound addition,could significantly improve the wettability between diamond and aluminum matrix,but their′s thermal conductivity were the worst,adding too many alloy elements in the aluminum matrix increased the precipitation of second phase,then the thermal conductivity of the samples were reduced.