反向等温挤压2024铝合金薄壁管的组织演化及增韧机理  

Microstructure evolution and toughening mechanisms of indirect isothermal extruded 2024 aluminum alloy thin-walled tube

作　　者：李琦伦 张晓波 乔及森[1,2] Li Qilun;Zhang Xiaobo;Qiao Jisen(College of Materials Science and Technology,Lanzhou University of Technology,Lanzhou Gansu 730050,China;State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou Gansu 730050,China)

机构地区：[1]兰州理工大学材料科学与工程学院,甘肃兰州730050 [2]兰州理工大学省部共建有色金属加工与再利用国家重点实验室,甘肃兰州730050

出　　处：《金属热处理》2025年第4期134-142,共9页Heat Treatment of Metals

基　　金：国家自然科学基金(52063017);甘肃省科技重大专项(20ZD7GJ008)。

摘　　要：利用SEM及TEM表征手段对反向等温挤压2024铝合金薄壁管及其退火处理后的组织演变及强韧性机理进行了研究。结果表明,挤压过程,由于塑性变形诱导细小S(Al_(2)CuMg)相沿挤压方向析出,同时保留均匀化态T(Al_(20) Cu _(2)Mn_(3))弥散相,T相兼具抑制再结晶和弥散强化双重作用,且产生高密度位错并形成亚晶结构,从而导致挤压态合金的抗拉强度增至304.73 MPa,断后伸长率达12.3%。退火处理后,S相部分粗化削弱析出强化作用,但位错缠结网络促进亚晶细化,并增强晶界钉扎效应,使塑性进一步提高(断后伸长率达15.7%)。同时,S相取向性减弱趋于等轴化,降低各向异性,使合金强度下降。Microstructure evolution and strengthening and toughening mechanisms of 2024 aluminum alloy thin-walled tube subjected to indirect isothermal extrusion and after annealing treatment were studied by means of SEM and TEM characterization techniques.The results show that during the extrusion process,plastic deformation induces the precipitation of fine S(Al_(2)CuMg)phase along the extrusion direction,while the homogenized state T(Al_(20) Cu _(2)Mn_(3))dispersed phase is retained,which plays a dual role of suppressing recrystallization and dispersion strengthening,and produces high-density dislocations and forms a subgrain structure.As a result,the tensile strength of the extruded alloy increases to 304.73 MPa,and the elongation after fracture reaches 12.3%.After the annealing treatment,the partial coarsening of the S phase weakens the precipitation strengthening effect.However,the dislocation entanglement network promotes the refinement of sub-grains and enhances the grain boundary pinning effect,further improving the plasticity(the elongation after fracture reaches 15.7%).At the same time,the orientation of the S phase weakens and tends to be equiaxed,reducing the anisotropy and resulting in a decrease in the strength of the alloy.

关 键 词：2024铝合金 反向等温挤压 组织演化 强韧性 

分 类 号：TG379[金属学及工艺—金属压力加工]