- Rolled Sheet Organization And Performance. AZ31 Magnesium Alloy Extrusion Research

Magnesium alloy sheets are promosing materials that can be widely used in aerospace,automotive,3C and other fields.However,because of the poor formability at room temperature,the traditional rolling must be carried out at higher temperatures,and it is so complex that the cost is unacceptable. Magnesium AZ31 sheets were prepared by extrusion and rolling method in this paper.The microstructure and properties of these sheets were studied.The extrusion,rolling and heatreatment parameters of magnesium AZ31 sheets were determined in this paper.X-ray diffraction(XRD), transmission electron microscopy(TEM),optical microscopy(OM),room temperature tensile tests,and other experimental methods were employed to investigate the microstructure,texture,and mecha nical properties of testing materials.Effects of texture on the mechanical properties were also discussed.The results show that:(1) The extrusion parameters are as follows:ingots were heated from RT to 380℃,with squeeze tube heated to 250℃;the extrusion ratio is 42.4 and the extrusion rate is 2 mm / s.The sheets were successfully extruded with its thichness of 1.5mm and width of 100mm according to the extrusion parameters above.(2) There are two main texture components,which are {0002} <1 0(?)0> and {1 0(?)0} <1 1(?)0>,getting from texture analysis.The results revealed by tensile tests at room temperature are as follows,basal slip as well as {1 0(?)2} pyramidal twinning is inhibited in extrusion direction un der tensile loads, which results in the highest yield strength(2OO.4MPa);for specimen s in the direction 45°to extrusion direction,basal slip is activated in grains with {1 0(?)0}<1 1(?)0> texture component,which results in the highest elongation percentage(19.0%);the yield strength in the direction 90°to extrusion direction is only half of its counterpart along extrusion direction,due to the occurrence of {1 0(?)2} pyramidal twinning in grains with {1 0(?)0}<1 1(?)0> texture component.(3)The average grain size of extruded sheets grew up from 37μm to 45μm after annealing 3h at 450℃.The intensity of {0002}<1 0(?)0> and {1 0(?)0}<1 1(?)0> texture components were increased significantly. {1 0(?)0}<1 1(?)0> texture component disappeared after hot rolled one pass at 400℃with 30%thickness reduction.The intensity of {0002}<1 0(?)0> texture component decreased significantly,mainly due to the rotation dynamic recrystallization(RDX) during the hot rolling process.In addition,the average grain size of the samples which were hot rolled at 400℃with 55% thickness reduction and annealing 1h at 200℃is less than 5μm.