Preparation of Mg-AZ31 based composites with Ti particles by friction stir processing

Mg-AZ31 based composites with 20%(volume fraction) and 40% Ti particles were fabricated by friction stir processing(FSP).The results show that after four FSP passes the matrix structure of composite layers can be significantly refined within 3-5 μm obviously,and the fragments of the Ti particles are about 200 nm.The Ti fragments in the composite layer with 20% Ti particles have inhomogenous distribution and demonstrate poor tensile properties and low elongation.However,the Ti fragments in the composite layer with 40% Ti particles have homogenous distribution and the tensile properties of composite layer are greatly improved,and the elongation of composite layer has no obvious change compared with that of matrix.Using the rule of mixture to predict the microhardness values of composite layers,the results approximately match the experimental ones.