Study On Infiltrability Of Zn-Al Alloy Into Carbon Fiber And Preparation Of Composite

Over the past30years, people have been looking for a material which iscombined with light weight, high strength, impact resistance, resistance tofatigue and corrosion. Aluminum alloy reinforced by glass fiber/epoxy laminatesalmost cover all these demands. However, there are a series of drawbacks in thecomposite materials, for example, low intensity of inter-layer combination,inclining to delamination, poor of high temperature resistance and easy to aging.One of the feasible methods to overcome these drawbacks is to replace thepolymeric materials in conventional FMLS with metallic materials.In this paper Zn-Al alloy connection agent instead of the traditional epoxiesand carbon fiber reinforced5052aluminum alloy by hot pressing in semi-solidtemperature. First, a study on impregnation of Zn-Al alloy to carbon fibers sheetis carried out. In the paper, the effect of the two variables temperature and alloycomposition on the infiltration of semi-solid Zn-Al alloy and penetration theoryhad been studied. and we choose the best impregnation Zn-Al alloy as metallicadhesives, and carbon fiber composites was prepared by hot pressing at theoptimum temperature and then combined with ultrasonic vibrations to get thefinal composite.Room temperature tensile properties (longitudinal stretching) were testedwith electronic universal testing machine; the microstructure of the compositelayer interface was observed and analyzed by scanning electron microscope (SEM); and a composition analysis was conducted by energy dispersivespectroscopy (EDS).The results show that:(1) Zn-8Al alloys and Zn-27Al in the same semi-liquid ratio showed solid carbon fiber impregnated with different properties. Zn-8Al alloy can be well impregnated into the carbon fiber sheet and Zn-27Al cannot impregnate fibers.(2) With the increasing of temperature on hot pressing,the liquid content increased as well, But the temperature and impregnation donot show a linear correlation.(3)The infiltration of semi-solid slurry during hotpressing can be evaluated by SFIR, which is inversely proportional to the slopesof the solidus and liquidus and to the value of Cs-Cl at the hot-pressingtemperature in the phase diagram. During a hot-pressing infiltration process, thelower the SFIR of the semi-solid slurry is, the stronger the infiltration will be.(4)Zn-8Al alloy was used as metallic adhesives and prepared by carbon-fibercomposites using hot pressing. Carbon fiber dispersed uniformly in metallicadhesives and integrated well. There was no shrinkage cavity, shrinkage porosityand other defects in adhesive. Under hot press and ultrasonic, the element wasdiffusion to be a layer between the substrate and Zn-Al alloy. the interface is ametallurgical bond (6) Carbon fiber volume fraction was found to reach24.7%,the tensile strength and elastic modulus of the composite panels are up to200Mpa and167Gpa by measuring the mechanical properties of the composites,tensile strength and elastic modulus of the composites, compared with matrix,were respectively increase by32%and50%.These results indicate that the impregnation of Zn-Al alloy in semi-solidslurries depends on SFIR value, the lower the SFIR of the semi-solid slurry is,the stronger the infiltration will be. The discovery of this principle will helpchoose other metallic binder. Zn-8Al as an intermediate linking agent can play agood role of the connection, comparing with the strength of the composite substrate, tensile strength and elastic modulus has been noticeably improved.