Effect Of Al And Ni On The Wetting Of Several Substrates By Zr-Cu Based Alloys

Zr-Cu based alloys have strong glass-forming ability and a wide supercooled liquidregion. To take advantage of the less complex equipment can more easily prepare goodquality Zr-Cu based bulk amorphous alloys. Meanwhile, Zr-Cu based bulk glass shows veryexcellent mechanical properties, but the low temperature ductility limiting its application.Researchers have added second phase to the amorphous alloy to maintain the originalexcellent properties while plastically was improved by blocking the genaration of a singleshear band and promoting the generation of multi-shear band. This shows that thedevelopment of amorphous alloy matrix composites is an effective way to expand theapplication of amorphous alloy.Wetting of amorphous alloy on the second phase plays an important role in the processof preparing the amorphous alloy matrix composites. While the emergence of the precursorfilm in the forefront of the three-phase line often indicates that the system has a goodwettability. So we can induce the precursor film appears to improve the wettability of thesystem by adding alloying elements. In addition, the metal matrix composites which regardgraphite as reinforced phase has a number of excellent properities have been widely appliedto the field of aviation industry. But the role of the alloying elements on infiltration is stillvery limited. So this article investigated the wettability of Zr55Cu45, Zr55Cu35Al10andZr55Cu30Al10Ni5three Zr-Cu based alloys on Al2O3, AlN, ZrC and graphite substrates. Inorder to reveal the impact of Al, Ni element on the precursor film and the penetration whichprovide a theoretical guidance for improving the wettability. The results of this study are asfollows:(1) As to the presence of the interfacial reaction systems ZrCu(Al,Ni)/(Al2O3, AlN), theformation of the precursor film is controlled by the competition between the adsorption rateof active atoms Zr to the three-phase line with the interface reaction rate. If the rate ofadsorption of the active atoms is larger than the interface reaction rate, the fronter ofthree-phase line appears precursor film. In Zr55Cu45/(Al2O3, AlN) systems, the Al elementwhich is displaced by the interfacial reaction with Zr and Cu atoms to form an intermetalliccompound, so that lower the melting point and increaser the fluidity of the alloy whichpromote the adsorption of Zr atom to the three-phase line and then promote the formation ofthe precursor film. The precursor film is mainly composed of Zr-rich film which has a little of Cu, Al atoms. When the precursor film formed, the droplets spread on it, so the wettabilityis improved.(2) The addition of Al and Ni elements reduce the activity of the Zr atoms in the alloyswhich increases the inert between alloy and substrate that greater widen the precursor film.The impact of Al, Ni is different in different systems. In the interfacial reaction involvedZrCu(Al, Ni)/(Al2O3, AlN) systems, the impact of Al on precursor film is larger than Ni. Inthe ZrCu(Al, Ni)/(ZrC) system which without interfacial reaction, the role of Ni is largerthan Al.(3) There is a different degree of penetration of three Zr-Cu based alloys on graphitesubstrate, the addition of Al and Ni elements reduce the intensity of interfacial reaction. Theaccumulation of reaction product in griphate holes lead to the decaease of infiltration.Analysis shows that the penetration depth linear change with time which proves reactiveinfiltration is controlled by the reaction product formation in the infiltration front and alongwith the wetting process of alloy on the reaction product. In addition, as the temperatureincreases, the contribution of spreading to the decrease of contact angle increases and thecontribution of infiltration to the decrease of contact angle decreases.