Research On The Microstructure And Properties Of(Grp+SICp)/AZ91 Magnesium Matrix Composites Processed By Hot Deformation

In this paper,a total of 4 kinds of magnesium matrix composites were prepared by semi solid stirring casting,respectively 5?m5%Grp/AZ91,5?m10%Grp/AZ91,?Grp+5?mSiCp?/AZ91 and?Grp+10?mSi Cp?/AZ91.The hot deformation was carried out subsequently.The effect of Grp and SiCp on the microstructure and wear resistance of the as-cast composites was investigated.The microstructure,mechanical properties and wear resistance of5?m5%Grp/AZ91 under different hot deformation processes were explored.The influence of SiCp on the wear mechanism of the as-extruded hybrid reinforced composites was clarified.The results show that after the addition of Grp with volume fraction of5%,the network-like distribution of Mg₁₇Al₁₂2 of as-cast AZ91 alloy turns into Mg₁₇Al₁₂2 and Al₄C₃ which distributed along graphite particles in the composite.Compared to the as-cast AZ91 alloy,the grain size of 5?m10%Grp/AZ91 is significantly refined,along with the obvious increasing of hardness and the wear resistance.After the Grp volume fraction comes to 10%,the grain size decreses,and the change of hardness is not obvious,and the wear rate is increased.With the increase of Grp content,the wear mechanism gradually transforms from abrasive wear to delamination wear.Compared to5?m10%Grp/AZ91,the addition of 5?mSiCp did not change the type and distribution of the second phase,but the hardness and wear resistance of the composites increased significantly.With the increase of SiCp size,the grain size increases slightly,and the hardness of the material remains unchanged,and the wear rate further decreases.After adding SiCp,the wear mechanism changes from delamination wear to abrasive wear.Compared to as-cast 5?m5%Grp/AZ91,the grain size and Grp size of the5?m5%Grp/AZ91 after 1FD decreases,and the mechanical properties increase.With the increasing of forging pass,the grain size first decreases and then increases,and the Grp size decreases gradually.The yield strength varies little,and the tensile strength and elongation gradually increase.Compared to5?m5%Grp/AZ91 after 1FD,the grain size and Grp size of the5?m5%Grp/AZ91 after 1FD+ED decreases,and the mechanical properties have been greatly improved.With the increasing of forging pass before extrude,the grain size decreased slightly,and the Grp size did not change.The mechanicalpropertiesincreasedslightly.Comparedtoas-cast5?m5%Grp/AZ91,the wear rate and friction coefficient of 1FD5?m5%Grp/AZ91 decreased whose wear mechanism is slight abrasive wear,and the wear rate and friction coefficient of 1FD+ED 5?m5%Grp/AZ91increased whose wear mechanism is serious abrasive wear.After 1FD+ED,the grain size and Grp size of 5?m10%Grp/AZ91decrease,along with increasing of the mechanical properties.After the addition of 5?mSiCp,the grain size increases,and the size of Grp decreases.The yield strength decreases.The tensile strength increases,and the wear resistance increases.With the increase of SiCp size,the grain size is further increased and the size of Grp is further reduced.The yield strength remains unchanged,and the tensile strength increases.The wear resistance is further improved.The wear mechanism gradually changed from delamination wear to abrasive wear.The wear rate of as-cast 5?m10%Grp/AZ91,?Grp+5?mSiCp?/AZ91 and?Grp+10?mSiCp?/AZ91 is unchanged before and after 1FD+ED,and the friction coefficient has been increased.