Study On The Influence Of Heat Treatment Process On The Microstructure And The Static And Dynamic Mechanical Properties Of Aermet100Steel

Aermet100steel with high strength and good toughness is expected to be used forearth penetrator shell, etc. When material under dynamic load, the mechanical behavior andinternal microstructure changes of materials different from that of quasi static deformation.Therefore, study on the dynamic mechanical response of Aermet100steel in this paper, inorder to provide theory support to its application in the weapon equipment.By changing the heat treatment of factors such as heating temperature, cooling, heatpreservation time, Aermet100steel was treated with different heat treatment experimentsprocess, and then analyzed the microstructure and quasi static mechanical behavior of thematerial, and get the best heat treatment process conditions. The split Hopkinson pressurebar that is installed with heating device are used to systematically study the mechanicalproperties under different strain rates and temperatures of Aermet100steel, get theinfluence of strain rate and temperature on the mechanical properties and the microstructureof Aermet100steel, get the best heat treatment process under dynamic conditions.Theevolutionary process of adiabatic shear band and the fracture mechanism under hightemperature and high strain rate are preliminary explored at last.Tempered at482℃after four kinds temperature quenching, the microstructures ofsamples are tempered martensite, undissolved carbides, a small amount of twinning andreverted austenite. Not dissolve carbide after850℃quenching is more and large comparedwith870℃,885℃,900℃, the samples quenched at885℃and tempered at482℃have thebest static and mechanical properties. Thus the quenching temperature is determined to be885℃. When quenched at885℃and tempered at different temperatures, the strength ofmaterials present a trend of increased first and then decreased with the increase oftempering temperature, there was a maximum value in the482℃tempering temperature.When the tempering temperature is600℃,the strength is the lowest,but the plastic andshock absorption function is improved. By comparison, in482℃tempering Aermet100steel has the best comprehensive mechanical properties, so to determine the final heattreatment process for885℃oil quenching (1h)+(80℃) cryogenic treatment (1h)+482℃tempering (5h).Under the condition of room temperature dynamic load, the strain rate of1000~ 4200s-1range, Aermet100steel is not sensitive to strain rate, but with the rise oftemperature rheological stress has a certain decline. By studying the quenching temperature,quenching method, cryogenic treatment and the influence rule of tempering temperature ondynamic mechanical properties of the material to reach the best heat treatment process for885℃quenching (1h)+oil quenching+cryogenic treatment (80℃,1h)+482℃tempering(5h), consistent with the best heat treatment process under static. The fracture mode ofmaterial are shear fracture, fracture surface there is stretched dimple, explain the fracturemode of Aermet100steel is still the ductile fracture under high strain rate.Under the condition of high temperature dynamic load, Aermet100steel exhibited acertain of softening effect and strain rate hardening effect. In the process of compression,shear band initiated at the bottom face on both ends of the cylindrical specimen easily, thenextended along the direction of maximum stress and shear band is45°to the center axis,present characteristics of the white band shear zone. The temperature stimulates theformation of the adiabatic shear band, in reducing the critical strain of the adiabatic shearband, also make the adiabatic shear band area more, the higher the temperature, the moreserious the tissue deformation.Strain rate increase can promote the generation of shear band,can promote the expansion of the shear band.