Injection Molding And Plasma Preparation Of Ti - 6, 4 V Process Research

Ti-6Al-4V is equiaxed martensite alpha+beta phase titanium alloy, with low density, high intensity, good corrosion resistance and mechanical properties etc, widely used in aerospace, shipbuilding, chemical industry, metallurgy, medical care and other fields, and has become the world’s universal titanium alloy. But the machining performance of titanium alloy is poor,so a lot of production of titanium alloy with complex shape product quite difficult. The paper study the process making of Ti-6A1-4V by metal powder injection molding(MIM) with characteristics of near net shape forming. On the other hand,Ti-6Al-4V is made by the spark plasma sintering(SPS) which can get fine grain, high density and execellent mechanical properties, save a lot of time and energy, desiring to enhance the titanium alloy products of the production efficiency.At present, the research of Ti-6A1-4V producted by MIM or SPS which are two advanced material processing technology is less in the domestic,especially there is not system research reported by material workers about Ti-6A1-4V made by SPS, In view of that, this paper study the low cost Ti-6Al-4V powders as raw material obtained by mechanical alloying(MA), adopts MIM and SPS different forming methods for preparation of Ti-6A1-4V alloy. The theoretieal analyses of experimental were conducted byseanning eleetron mieroseopy(SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis(EDXA), X-ray diffraction analysis(XRD) and optieal mieroscopy.The process of Ti-6A1-4V powders made by mechanical alloying (MA), the ductile Ti powders and the brittle6A1-4V powders will form layered composites, and sustained refinement with the ball-milling time. When it reaches a certain level, the aluminum of6A14V will be taken over by titaniuim, and it inleakage in the lattice of titaniuim to form a solid solution. So the lattice parameter of titaniuim will increase, on the other hand, titaniuim and vanadium will form mutual solid solution as the beta, its peak of XRD become sharp.The process of making MIM Ti-6A-4V alloy using the powdes of MA was studied.An LDPE-Wax-SA traditional binder system with Powder loading65vol% was injeetion molded.The optimal molding parameters for the feedstoek are as following:temperature for molding140℃, press for molding120MPa, speed for molding60%, dwellpressure for molding20MPa.Two steps of debinding were used in the study.Firstly, green parts were dipped into the solvent CH4Cl2for8hours with the debinding rate up to50%-55%. Then themal debinding began in Ar atmosphere at the550℃with the following Process to remove remanent binder.During the process of sintering,Ti6A14V were obtainedin the high vacuum with the temperature of1200℃for4h. The thickness of the sample is91.71%,compressive strength is696.232MPa, The fracture mode is cleavage frature.The process of making SPS Ti-6A-4V alloy using the powdes of MA was studied.the sample obtain excellent machanical properties with homogeneous microstructure, fine grain and there were no appearing of grain abnormal grew-up and reunion.The fracture mode is cleavage frature。.when the sintering temperature is1100℃, Compression strength of the sample using the ball-milling time40hour of powders is1885.19MPa.