铸态工业纯铝1A85的CVCE变形特征

Deformation characteristic of as-cast commercial pure aluminium 1A85 by CVCE

采用连续变断面循环挤压(CVCE)工艺制备细晶工业纯铝,结合铸态工业纯铝1A85沿宽度、厚度、高度方向上组织和显微硬度的变化,得出CVCE工艺变形特征。结果表明:铸态工业纯铝1A85经1次循环变形后,组织得到明显细化,晶粒尺寸显著减小至33.5μm,是原始试样的2/3,试样的显微硬度增大至52.97HV,相比原始组织提高2倍;纵截面上原始的等轴晶粒取向性逐渐削弱,晶粒沿纵向拉长,横截面上原始粗大的柱状晶粒取向性几乎消失;在厚度、高度方向,试样受挤压力和剪切力由表面至芯部逐渐减小,晶粒尺寸沿表面至芯部逐渐增大,在宽度方向,试样仅受模具约束力,晶粒尺寸沿表面至芯部变化不明显;硬度变化与晶粒尺寸变化相反,符合细晶强化规律。

Combined with the variation of microstructure and micro-hardness of fine grain as-cast commercial pure aluminium1 A85 along the width,thickness,and height direction by CVCE technique,the deformation characteristic of continuous variable cross-section recycled extrusion（CVCE）was obtained. The results show that the microstructure is refined and grain size decreases distinctly to 33.5 μm after one recycled deformation,which is two-thirds of the original sample. The micro-hardness increases obviously to 52.97 HV,which is 2 times higher than that of original samples. The orientation of original equiaxed grains gradually weakens on longitudinal section,and the orientation of original coarse columnar grains almost disappears on cross section. Along the thickness and height direction,the subjected extrusion force and shear force of samples gradually reduce from surface to center,the grain size gradually increases from surface to center. In addition,the change of grain size from surface to center along the width direction is not obvious because the samples are only subjected to mold binding force. The change of micro-hardness is opposite to the change of grain size,which accords with fine grain strengthening rule.