Study On The Properties Of AI₃Ti Particle Reinforced Aluminum Matrix Composites Fabricated By In Situ Synthesis

Ti-Al intermetallic has excellent strength at high temperature,stiffness and creep resistance,oxidation resistance and abrasion resistance and other excellent performance,especially Al3Ti possesses the best property,so it is the ideal of light and high temperature structural materials,so the researchers begin to study its property.But it has low plasticity,low room temperature ductility and big brittleness,so that affects its application.This research chooses titanium mesh as the reaction source,with a purity of 99.00%aluminum metal as the substrate,it is preparation of Al3Ti particle reinforced aluminum matrix composite by in-situ reaction method under different process conditions.By optical microscope(OM),XRD,scanning electron microscope(SEM)and energy spectrum(EDS)analysis of the microstructure of the composite material,the interface bonding and the composition of the phase,the analysis of phase of the chemical composition of the composite.The hardness and friction and wear of composite material are tested by microhardness tester and friction wear testing machine.The results show that appropriate hot-pressing temperature and hot-pressing pressure can form a neat coarse sample,it makes the sample come out liquid flowing under high temperature and high pressure,not forming structured organization.So the appropriate pressure is 10MPa,thermal insulation temperature is 660?,holding time is 5min.By controlling the variable method,cross-sectional profile of the different composite material is studied about the reaction temperature parameter from 665? to 900? and the reaction time parameter from 5min to lh,with the increase of heat treatment temperature and holding time,the Al3Ti is constantly increasing.But there is no more reaction at low temperature and time and organization is not uniform.Heat preservation temperature and heat preservation time is too high,it can't form a uniform organization,however it form the strips,so suitable heat preservation temperature is 850?,the suitable time of heat preservation is lh.In results about hardness,hardness of composite under 850? is 11 times higher than that of the matrix materials,but homogeneous composite material is higher hardness than heterogeneous composite material,it increases by about the percent of 20,reaction completely block organization is higher than reaction completely banded organization,it increases by about the percent of 5.In the experiment about friction experiment,the average friction coefficient is from decrease to increase with the rise of temperature under the temperature of 660?,850? and 900? and constant time of lh,in turn,it is 1.2,0.4,0.8.So the wear-resisting performance of the composite under 850? is best.The wear rate of the reaction completely uniform lumpy composite materials is lower than that of other types,the wear rate of the complete reaction of the massive organization is about 5 times than that of the matrix.The reason is that the existence of Al3Ti can resist wear.In the wearing process of the composite,there are adhesive wear and abrasive wear mechanism,the later is the key.