High Temperature Behavior Of Mg-Sn-Y Alloy Based On Solid Solution Strengthening And Second Phase Strengthening

Mg-Sn-Y alloy,as a new heat resistant magnesium alloy,has broad research potential.Based on the theory of solid solution strengthening and second phase strengthening of the alloy,this paper explores the high-temperature deformation behavior of the Mg-Sn-Y alloys by observing the microstructure,analyzing the type and distribution of the second phase,constructing constitutive equations,drawing the processing maps and testing mechanical property.Results have been reported that:1.The high temperature stress,deformation stress index and apparent activation energy can be significantly increased by solid solution Y element of Mg-Sn binary alloy.Which will change the plastic deformation control mechanism.It is also found that the solid solution Y element would restrain the dynamic recrystallization,increase the processing instability area.2.There are four secondary phases in the alloy:Mg₂Sn?Sn₃Y₅?Mg₂₄Y₅&MgSnY.Among them,Mg₂Sn and Sn₃Y₅ are the easiest to generate.We can speculate that Sn₃Y₅ has better high temperature stability and strengthening effect than Mg₂Sn.3.Five Mg+xSn3Y5?x=0,0.5,1.0,1.5,2.0 wt.%?alloys are smelted by means of external addition.It is found that the interface between the Sn₃Y₅ powder and the magnesium matrix did not match,resulting in poor mechanical properties.The Sn₃Y₅ phase spontaneously generate in the Mg-0.45Sn-0.55Y?wt.%?alloy could play a significant strengthening effect,When the temperature comes to 350?&400?and strain rate becomes 10^-4 s^-1.4.The extruded Mg-0.45Sn-0.55Y?wt.%?alloy,in which Sn₃Y₅ can be spontaneously generated,has good mechanical properties.At room temperature,its tensile yield strength is164.2MPa,tensile strength is 239.1MPa,and the elongation is 10.6%.While the temperature comes to 200?,its tensile yield strength is 89.1 MPa,tensile strength is 142.1 MPa,and the elongation is 38.4%.