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利用3D转模等通道转角挤压(3D-RD ECAP)设备,对AZ31镁合金进行了A′,B′_A,B′_C与C′4种路径的ECAP实验。对试样的显微组织观察显示,经4种路径挤压后合金显微组织都明显细化,但不同路径对微观组织和力学性能的影响不同。经A′和B′_A路径挤压的试样组织中晶粒尺寸和硬度分布比其它两种路径挤压的试样更均匀,且显示出更高的塑性。通过对各种路径挤压过程中试样内部立方单元的变形分析,揭示了传统的剪切模型理论的不足。利用有限元方法模拟了试样ECAP的形变过程,证实材料在变形过程中各部位受力差异很大。ECAP对试样变形的均匀性主要取决于拉/压应力交替作用于试样各个部位的顺序,而与传统剪切模型中的立方单元变形规律没有直接关系。
ECAP experiments of A ’, B’_A, B’_C and C’4 pathways were carried out on AZ31 magnesium alloy by means of channel turn angle extrusion (3D-RD ECAP) such as 3D rotary die. The microstructure observation of the sample shows that the microstructures of the alloy are obviously refined after being pressed by the four paths, but the influences of different paths on the microstructure and mechanical properties are different. The grain size and hardness distribution of the specimen extruded through the A ’and B’_A paths is more uniform than that of the other two paths and shows higher plasticity. The deformation analysis of cubical elements inside the sample during the extrusion of various paths reveals the shortcomings of the traditional shear model theory. The deformation process of sample ECAP was simulated by finite element method, and it was confirmed that there was great difference in the stress of each part in the deformation process. The uniformity of ECAP deformation depends mainly on the order in which the tensile / compressive stress alternately acts on each part of the specimen, which is not directly related to the deformation law of cubic elements in the traditional shear model.