TC11钛合金搅拌摩擦焊接头微观组织和力学性能研究  

Research on Microstructures and Mechanical Properties in Friction Stir Welded Joints of TC11 Titanium Alloy

作　　者：王欣 谢文辉 娄正计 刘宏 杨冠军[1] 何光宇[2] 周利 Wang Xin;Xie Wenhui;Lou Zhengji;Liu Hong;Yang Guanjun;He Guangyu;Zhou Li(State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China;Science and Technology on Plasma Dynamics Laboratory,Air Force Engineering University,Xi’an 710038,China;Shandong Provincial Key Laboratory of Special Welding Technology,Harbin Institute of Technology at Weihai,Weihai 264209,China)

机构地区：[1]西安交通大学金属材料强度国家重点实验室,陕西西安710049 [2]空军工程大学等离子体动力学重点实验室,陕西西安710038 [3]哈尔滨工业大学(威海)山东省特种焊接技术重点实验室,山东威海264209

出　　处：《稀有金属材料与工程》2022年第4期1436-1441,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金青年科学基金(51305335)。

摘　　要：在不同转速下开展了TC11钛合金搅拌摩擦焊试验,分析了接头的微观组织和力学性能,建立了焊接工艺、接头组织与性能之间的内在联系。结果表明:接头搅拌区(SZ)为完全的β转变组织,其细小晶界α相和晶内片层状α+β相以及针状α′相的双重强化作用,致使SZ硬度最高。热影响区(HAZ)和热机影响区(TMAZ)均由残余初始α相和β转变组织组成,但后者具有一定的流变特征,且距SZ越近,转变组织占比越大,强化效果越明显。随着转速的上升,SZ中晶界α相和晶内片层状α+β相的尺寸增加,晶内针状α′相的含量降低,这引起了其硬度的降低。与硬度规律相同,各转速下接头拉伸均断裂在母材区(BM),且各转速下SZ抗拉强度明显高于BM,并随转速上升而下降。此外,SZ中细小的晶界α相和晶内片层状α+β相,也导致各转速下SZ延伸率高于BM,使其展现出良好的塑性,且随着转速上升,因晶界α相和晶内片层状α+β相尺寸增加,SZ延伸率有所降低。Friction stir welding test of TC11 titanium alloy was carried out under different rotational speeds,the microstructures and mechanical properties of the welded joints were analyzed,and the relationships among processing parameters,microstructures and properties of the joints were established.The results show that the SZ is characterized byβtransformed microstructure,which contains grain boundaryαphase,intragranular lamellarα+βphases and acicularα′phase.The double strengthening is caused by the fineαphase andα+βphases as well as the presence ofα′phase,which leads to the highest hardness value in the SZ.The retained originalαphase andβtransformed microstructure are found in the HAZ and TMAZ,while the TMAZ shows the streamlined deformation characteristics.The proportion ofβtransformed microstructure in these zones is higher when closer to the SZ,and thus the strengthening effect is enhanced.The sizes ofαphase andα+βphases increase and the content ofα′phase decreases with the rotational speed ascending,which results in the reduction of hardness value in the SZ.Similar to the law reflected from the hardness test,all the joints fracture in BM after tensile test,the tensile strength of the SZ under different rotational speeds are significantly higher than that of BM,and they decrease with the ascent of rotational speed.Besides,the fineαphase andα+βphases cause the higher elongation of SZ compared with that of BM,meaning that the SZ has good plasticity.With the rotational speed ascending,the elongation of SZ decreases owing to the increase of the sizes ofαphase andα+βphases.

关 键 词：搅拌摩擦焊 TC11钛合金 微观组织 力学性能 

分 类 号：TG456[金属学及工艺—焊接] TG146.23[一般工业技术—材料科学与工程]