6061铝合金等通道转角挤压时的流变性能  

Flow properties of 6061 aluminum alloy processed by equal channel angular extrusion

作　　者：董洪波[1] 黄映霞[1] 

机构地区：[1]南昌航空大学航空制造工程学院,江西南昌330063

出　　处：《材料热处理学报》2011年第2期70-74,共5页Transactions of Materials and Heat Treatment

基　　金：国家科学基金资助项目(50964012)

摘　　要：分别对退火态和固溶时效态6061铝合金进行8道次及4道次等通道转角挤压,用有限元软件Deform-3D模拟变形过程,研究连续大变形对组织性能的影响规律。结果表明:等通道挤压使晶粒破碎细化,金属流线走向与剖面对角线方向基本一致;退火态合金的表面硬度随变形道次增加而升高,各道次挤压载荷峰值没有随着变形道次增加而单调增加,而是经历一个升高、降低、再升高的过程。固溶时效态合金的表面硬度在2道次变形后达到了峰值,其载荷峰值也在第2道次变形时最高。硬度值的变化规律与强化因素及位错的运动有关,而载荷的变化规律与摩擦力的变化及其对载荷的贡献大小有关。模拟结果发现,挤压载荷峰值随着变形道次的增加而增大,与实测值不相符。由于剧烈变形使合金组织性能变化较大,因此需要适当修正材料本构关系,才能正确反映其流变行为。Extrusion deformation experiments for annealed and solution-aged 6061 aluminum alloy were carried out by using equal channel angular extrusion（ECAE） technique.The samples were extruded in the ECAE die for eight and four passes at room temperature,respectively.Meanwhile,the deformation behavior of the alloy was simulated by FEM using software Deform-3D.The deformed microstructure and flow properties of 6061 aluminum alloy were investigated.The results show that the grains are refined by equal channel angular extrusion,and the metal flow lines distribute nearly along the diagonal direction on longitudinal section.The surface hardness of annealed 6061 aluminium alloy increases continuously with increasing the ECAE passes.However,the peak value of deforming load in each ECAE process does not show monotonic increase with increasing passes,but rises at first,then falls down,and increases again.The maximum surface hardness and maximum deforming load of the solution-aged 6061 aluminium alloy occurs after ECAE for two passes.Surface hardness of the alloy depends on its strengthening mechanisms and movement of dislocations,and deforming load is related to the friction of ECAE die and sample and material strength.The simulation shows that the peak value of deforming load for each ECAE pass increase slowly with increasing of strain,so the calculated values are not in agreement with the measured ones.In order to characterize the flow behavior of the alloy correctly,the constitutive relationship of the material should be modified properly due to the change of its microstructure and properties greatly with severe plastic deformation.

关 键 词：6061铝合金 热处理 等通道转角挤压 流变性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]