Investigation On Rolling Process And Interface Morphology Of Mg/Steel Composite Plate

Magnesium alloy is the lightest metal materials in Engineering application,has a specific strength and specific stiffness,good thermal conductivity and high damping shock absorption,electromagnetic shielding,but the strength of the magnesium alloy is low,easy to corrosion,toughness and high temperature creep resistance is poor,the price is higher,seriously hinder the further development and application,Using magnesium/steel composite structure,taking advantages of the two form a complementary effect,can keep high strength with high toughness and effectively reduce the structure weight at the same time.SPCC/AM60/SPCC composite plate were prepared by conventional rolling technology,an annealing process are need to improve the mechanical properties,the effect of rolling reduction and annealing time on microstructure and mechanical properties were studied.The results showed with higher reduction,the thickness ratio of steel and Mg increased,ferrite grains in steel matrix elongated and refined with forming fibrous tissue,Al rich transition layer formed and becomed uniform,and the ultimate tensile strength of composite increased at first and stayed constant with about 6%elongation.The ultimate tensile strength of composite with 60%reduction was 441MPa,fracture morphology showed a better bonding interface in higher reduction.An uniform transition layer,with a width of 0.78?m,formed in interface of magnesium/steel composite 8h annealed at 380?.The ultimate tensile strength of composite without annealing were 431MPa and 138MPa higher than the original material but UE were low,only 3.6%,and the ultimate tensile strength of composite 8h annealing at 380?slightly decreased to 422 MPa,UE was 7.9%and double than the rolling.0.78?m wide FeAl₂ phase transition layer improved the mechanical properties.Failure mechanism of tensile test was when the load is low,composite as a whole under tensile stress,when the load increased in a state of instability,the substrate layers shared tensile load,Steel and Mg substrate produced necking phenomenon,eventually caused fracture as a whole.Figure 42,Table 7,Reference 62.