Effects Of Equal Channel Angular Pressing On Microstructure And Properties Of Mg-1Zn-1Mn Alloy

Magnesium alloys are widely used in aerospace, automotive and electronic communications because of their low density, high specific strength and good electromagnetic shielding characteristics and have broad prospects of development and application as implant materials in medical field, and draw much attention, of scientists. The properties of magnesium alloys are of essential importance for their medical application. In this paper, Zn and Mn was used as the alloying elements and Mg-1Zn-1Mn alloy was processed by direct extrusion and ECAP deformation. The microstructure, mechanical properties and corrosion behavior of the extruded and ECAPed Mg alloys with different passes were discussed. The following conclusions may be drawn from this study:(1) ECAP can refine grains and change size and distribution of the second phases. The extruded alloy has an average grain size of about 5.08 ?m. The average grain size of the ECAPed Mg alloy for 1 pass, 2 passes and 4 passes is 4.89, 4.12 and 5.11 ?m respectively.After ECAP, secondary particles become smaller and more homogeneously distributed.(2) Compared with extruded alloy, the ECAP processed alloy has lower hardness and tensile strength but higher elongation to failure. The tensile strength of the Mg alloy decreases with increasing the number of ECAP passes. The hardness and elongation of the 2 passes ECAPed Mg alloy are the highest.(3) After one ECAP pass, the radius of capacitive loop and electron transfer resistance are all maximum, the corrosion rate is smallest, and the corrosion resistance of the magnesium alloy is proved the best.(4) After immersion in SBF solution for 72h at 37?, the corrosion products of the Mg alloy is composed of HA(Ca10(OH)2(PO4)6)?CaCO3 and Mg(OH)2. The corrosion product layer is dense for the extruded and 1 pass ECAPed Mg alloy, while the layer is loose and porous for the 2 passes and 4 passes ECAPed Mg alloy.