B < Sub > 4 < / Sub > 6061 Cp/thermal Deformation Characteristics Of Aluminum Matrix Composites And The Processing Figure

Aluminum matrix composites(AMCs) have a lot of adventages like high specific strength, high specific modulus, good high temperature performance and good abrasion resistance. These advantages make AMCs had great application prospects in aerospace and other fields. Due to the existence of hard particles in AMCs, hot-working ability of the material was much worse than the ability of aluminum alloy. Therefore, the research of B4Cp/6061composites’hot deformation behavior has important theoretical significance and application value..In this paper, isothermal compression tests are performed by using the Gleeble-1500thermal simulator. The hot deformation behavior of B4Cp/6061composites is investigated, and the effect of temperature and strain rate on the flow stress is analyzed. The processing maps of the B4Cp/6061composites which are developed based on Dynamic Materials Model, combined with the optical microscopy and SEM, are used to study high temperature deformation and microstructure evolution of B4Cp/6061composites. The following conclusions are drawn:(1) The effect of friction on this experiment is notable, and the modified flow stresses are less than the original data. As the deformation progresses, the effect of friction is growing.(2) As showed in stress-stain behavior curves of B4Cp/6061composites, the flow stresses are strongly influenced by deformation temperature and strain rate during high temperature compression. It decreases with the increase of deformation temperature and the decrease of strain rate. The initial deformation, the flow stress increases with increasing strain, show a clear hardening effect, and fall down after a peak value.Along with the deformation increases gradually reduce the flow stress, B4Cp/6061composites are noticeable softening.(3) The hot deformation constitutive equation is built by regression method, and the four characteristic constant of B4Cp/6061composites is calculated as following:stress exponent n=6.078, stress level parameter α=0.019mm2/N, structure factorA=1.62×1010s-1, deformation activiation energy Q=151.27kJ/mol.(4) Based on the theory of processing map and the dynamic material model, the processing map of B4Cp/6061composites is developed, and the results showed that:In condition of true strain0.9, the optimum hot working region is that temperature is480～500℃and strain rate is0.02-0.05s-1. In this region, power dissipation efficiencies are maximum, have a peak efficiency of58%, and correspond with the stable region.