基于物理模拟的相变塑性应变分离方法

Experimental extract of transformation plastic strain during phase transformation

相变塑性是材料在相变过程中由于外部应力引起的材料的不可逆变形。在大型金属零件的焊接和热处理等复杂热力循环过程中,相变塑性对残余应力和变形的影响不可忽视,因此,对材料的相变塑性开展研究十分必要。文章以马氏体相变塑性为例,采用施加不同单轴载荷水平的热力循环实验确定材料相变塑性;通过对该过程热力循环变形和组织演化的分析,在考虑弹性应变、热应变、组织应变基础上,得到了材料相变塑性应变随温度和应力变化的定量关系式。研究结果为分析和研究钢铁材料焊接和热处理过程中复杂热力行为提供了方法。

Transformation plasticity is inverse deformation during phase transformation under low loading. During the welding and heating treatment, accompanying with the complicated thermo-mechanics processes, transformation plasticity has great influence on the distortion and distributing of the residual stress in workpiece, so it is essential to research the transformation plasticity of the materials. By applied varied uniaxial load, an experimental method of determined transformation plasticity of materials is introduced. The total strain was decomposed by considering elastic strain, thermal strain, metallurgical strain and transformation plasticity strain, then the transformation plasticity strain were gained. Moreover, the quantity law for transformation plasticity strain of materials under different applied load and temperature was yielded. These results can provide a method for research the thermal-mechanics behavior of iron and steel workpiece after heat treatment or welding.