The Fabrication And Properties Analysis Of High Temperature Metal-Ceramics Composite Material

Ultra high temperature metal-ceramic composite materials have important application prospect in aviation.This paper mainly studied the characteristic and mechanics performance of NbMo based composites and TiC enhanced Ti-based composite materials.High density of ZrB2/SiC enhanced NbMo based ceramic composite materials were prepared by hot pressing sintering process.Analysis and research of the composites was achieved by SEM,XRD and other analytical test methods.The bulk density was measured using the Archimedes’ technique.The Vickers hardness was measured using a microhardness tester(FM-300)The corresponding crack sizes were determined using an optical microscope attached to the indenter.Compression tests were conducted in air at room temperature by a compression testing machine.The results shows that,Nb and Mo formed a homogeneous solid solution,small ZrB2 particles distributed uniformly in the NbMo solid solution matrix,The size of ZrB2 is about 1～2μm.The microstructure of the four samples are basically the same,the dark grey phase is solid solution rich in Nb,the light grey phase is solid solution rich in Mo black particles is ZrB2.The rich niobium area and rich molybdenum area distributed uniformly.Combined with the density,hardness and compressive strength,the strength of the four kinds of materials have greatly improved compared with the pure NbMo or ZrB2 ceramic.This is the result of a variety of reinforcement mechanism combined together.In this paper,the mainly reinforcement mechanism is the solid solution strengthening and particle strengthening effect.the density of A2 is 95%,while its compressive strength is up to 1974.17 MPa,it is obviously that for metal ceramic composite materials,the high density one of the key to improve the strength.In order to study the performance of the TiC enhanced Ti-based composite materials,in this paper,we prepared a cladding layer with a thickness of 2 mm on TC4 plate by laser cladding method.Pure Ti powder,C powder,and Ti40Ni20Zr20Cu20 amorphous powder were added into the cladding layer.The cladding layer and substrate formed a good metallurgical bonding,a few tiny holes can be found in the coating,it is because that the gas did not escape timely during solidification.Analysis of the coating was achieved by SEM,XRD,the results show that,Ti powder and C powder in the cladding layer generated hard ceramic TiC by in-situ reaction,part of Ti-base amorphous powder crystallized and formed inter-metallic compounds,part of them still exist in amorphous form.The coating exhibits a two-phase microstructure,dendritic and granular TiC dispersed in the Ti-based matrix.The microhardness tests showed that the coating present higher microhardness are 5-6 times harder than the TC4matrix.