Deformation division of metal flow behavior during extrusion process of 7075 aluminum alloy

Abstract：To reduce defects caused by non-homogeneous metal flow in conventional extrusion, a die with guiding angle was designed to improve the metal flow behavior. The characteristic quantities such as the second invariant of the deviator stress J2 and Lodes coefficient p were employed for the division of deformation area. The results show that when the metal is extruded with the guiding angle, no metal flow interface forms at the containers bottom, the dead zone completely disappears, the deformation types of the metal in the plastic deformation area change from three types to one type of tension, and the homogeneity of the deformation as well as metal flow are greatly improved. The non-homogeneous metal flow at the final stage of extrusion is improved, reducing the shrinkage hole at the axis end. The radial stress of the furthest point from the axis is transformed from tensile stress to compressive stress and the axial stress, and decreased from 70.8 to 34.8 MPa. Therefore, the surface cracks caused by additional stress arc greatly reduced. 作者： Author： LI Feng[1]  CHU Guan-nan[2]  LIU Xiao-jing[1] 作者單位： College of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150040, ChinaCollege of Shipping, Harbin Institute of Technology at Weihai, Weihai 264209, China 期 刊： 中南大學(xué)學(xué)報(bào)（英文版）   EISCI Journal： JOURNAL OF CENTRAL SOUTH UNIVERSITY OF TECHNOLOGY(ENGLISH EDITION) 年，卷(期)： 2009, 16(5) 分類號(hào)： Keywords： extrusion process    flow defect    deformation division    機(jī)標(biāo)分類號(hào)： V1 TM 機(jī)標(biāo)關(guān)鍵詞： aluminum alloy    during    metal flow    compressive stress    plastic deformation    additional stress    improved    tensile stress    conventional    axial stress    interface    axis    area    type of    tension    results    three    stage    final    hole 基金項(xiàng)目： the Excellent Young Teachers Program of Harbin City, China

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