Study On Mechanical Behavior And Deformation Of SiC_p/Al Composites Based On X-ray

High volume fraction silicon carbide particle reinforced aluminum matrix(SiC_p/Al)composites are widely favored for their good mechanical properties.However,at the mesoscale scale,there are few studies on the mechanical properties and damage with in-situ real-time of SiC_p/Al composites.This is not good to understanding the deformation and damage process of materials,and also makes theoretical simulations lack effective and intuitive experimental data.Based on synchrotron radiation X-ray phase contrast imaging technology,two kinds of particle gradation(45?m and 100+45?m)of SiC_p/Al composites are loaded by quasi-static compression through small material testing machines.The damage mechanism of SiC_p/Al composites was studied by X-ray digital image correlation method and synchrotron radiation X-ray computed tomography.The following research conclusions were obtained:(1)According to the stress-strain curve,the change of yield strength of SiC_p/Al composites caused by the difference in size distribution of SiC particle is small,but the maximum strength and ductility of 45?m SiC_p/Al are better than 100+45?m SiC_p/Al.(2)The image speckle quality was evaluated on X-ray phase contrast imaging images,and the errors of X-ray digital image correlation method(XDIC)was analyzed.The errors of displacement field and strain field were quantified.Finally,the radius of the subset of the XDIC in this experiment is 19 pixels,the displacement error is less than 0.02 pixel,and the strain radius is 15 pixels,the strain error is about0.08%.(3)The strain field of deformation different stages of SiC_p/Al composite was analyzed by XDIC.The results show that the 100+45?m SiC_p/Al deformation is more uneven,and the strain concentration zone grows and aggregates faster,resulting in the material breaking earlier than 45?m SiC_p/Al.(4)The recovery analysis of SiC_p/Al composite compression fractures by scanning electron microscopy and computed tomography showed that:The failure modes is no significant difference between the two composite materials.There are a lot of cracks around the fracture of the material,the number of cracks gradually decreases with the distance from the fracture increases.Hole nucleation is easily induced at the sharp corners of some particles and where the particle distribution is dense,eventually forming a crack source.The 100+45?m SiC_p/Al composite has a rougher section and more cracks around the fracture.The fracture surface of 45?m SiC_p/Al is relatively flat,the fracture roughness is small,the number of cracks around the fracture is relatively small,and the cracks are randomly distributed in a?worm?shape.