Rapid Preparation And Investigation On Properties Of TC4 Matrix Reinforced With TiB Whiskers And TiC Particles

TiB and TiC have been regarded as the best reinforcement for Titanium and its alloys for their shared physical properties like coefficient of thermal expansion and density.In addtion to that,TiB contributes to form a stable and clean surface between reinforment and the titanium ally matrix,while TiC proves ideal to enhance abrasive resistance of the composition,which makes TiB and TiC most preferred as reinforcement to enhance the titanium alloys.However,researches by far mostly focused on the fabrication of titanium alloy composites reinforced by TiB or TiC via tradtional methods like hot-pressing,which can lead to an unexpect growth of matrix grains.Some composites like these can fail before their yielding point.Spark Plasma Sintering,also known as SPS,is a newly developed technology to fabricate materials rapidly with expected grain size.As far as we are concerned,little reports have been published about the fabrication of titanium alloy composites reinforced by(TiBTiC).In this research,(TiB-TiC)/TC4 composites with different volumes of reinforcement were fabricated by SPS.The phase composition,density,tensile properties under room and high temperature,microstructure were also investigated as well as the mechanism of reinforcement.In this research,four different mixture powders(with reinforcement contents of 0 wt.%?3.15 vol.%?6.32 vol.%?9.5 vol.%)and four tensile test temperatures were used.All composites were synthesized by SPS process with low initial pressure of 1 Mpa,high holging pressure of 35 Mpa,dwell time of 5min and heating rate of 100?/min.Some conclusions can be drew from this research that:1)Under room temperature,the tensile resistance of composites goes up with increasing content of reinforcement,while ductility goes the opposite.Under high temperatures,he tensile resistance of composites goes up with increasing content of reinforcement,while ductility goes up then down.2)The grain-refinement effect plays the most important role in strengthening the composite,then comes TiC particles and TiB whiskers sharing the rest contribution.3)The failure of composites under room-temperature can be attributed to the cracks within quasi-continuous reinforcement,however under high temperatures it is the decohesion between matrix and reinforcement that should be blamed as the matrix gets softened.