The Influence Of Texture On High-cycle Fatigue Property Of AZ31B Magnesium Alloy

Base on the advantage in propery of weight and strength etc., magnesium alloy is provided with the great potential to be used in traffic, military affairs, space transport etc.. However the application of magnesium alloy is limited due to the unstable mechanic properties especially fatigue property.This paper analysed the mechanism of fatigue property with the high-cycle fatigue mechanine; the fatigue crack propagation of magnesium alloy is studied by (CT) sample, and the texture of magnesium is tested by using X-ray diffractometer. The effective of the texture on fatigue property and fatigue crack propagation in different directions are analyzed.Textures of 10 mm and 2 mm magnesium alloy plate were tested. The results show that obviously texture and anisotropy were observed in the AZ31B magnesium. As the times of extrusion basal texture (0002) was gradually weakly and travsversed to non-basal texture. The influences of texture on the anisotropy of fatigue property were stronger in 2 mm plate than that of in 10 mm plate. The schmid factors of basal texture were zero both on extrusion direction and transverse direction. The slip-systems will not start in both directions. The schmid factors of non-basal textures are larger in extrusion direction than transverse direction. Plastic deformation would accomplected because of the strat of slip-system. As a result of this, great stress would contain before the form of fatigue crack in ED. Otherwise the Schmid factors are smaller in TD compared with ED. So it is difficult to Plastic deformation. And texture made the crack hard to propagate.The influence of texture in 10 mm plate on the fatigue property both in ED and TD was studied. As the difference of Schmid factors, plastic deformation is easier in ED than in TD. As the results of the fatigue test the fatigue strength at 2×106 cycles in the two directions are 116.1 MPa (ED) and 105.3 MPa (TD). Endurance limits of the two directions at 5×106 are 107.7 MPa (ED) and 95.4 MPa (TD).The influence of texture in 2 mm plate on the fatigue property both in ED and TD was studied. Texture in 2 mm plate is complicated than that in 10 mm plate. And greater difference of Schmid factors in ED and TD would be found. Plastic deformation is easier in ED than in TD.Fatigue strength at 2×106 cycles in the two directions are 120.1 MPa (ED) and 104.5 MPa (TD). Endurance limits of the two directions at 5×106 are 112.5 MPa (ED) and 92.5 MPa (TD).The fatigue crack propagation rate of AZ31B was tested and the da/dN-ΔK cure which directly reflects the property of fatigue crack propagation. The mechanism of fatigue crack propagation was analysised and the effective of texture on the path and speed of crack propagation.