摘要
采用不同工艺参数制备了AZ40M/AZ61A异种镁合金搅拌摩擦焊(FSW)接头,借助体视显微镜、光学显微镜、扫描电镜、显微硬度仪与万能试验机研究了焊接接头的宏观形貌、显微组织、力学性能及断口特征。结果表明:使用锥形螺纹搅拌针可获得致密的焊接接头,而使用无螺纹搅拌针获得的接头焊核区存在孔洞及隧道型缺陷。FSW接头焊核区因动态再结晶而形成较细小的等轴晶,且因板厚方向上的温度差异,焊核区厚度方向上晶粒尺寸存在偏差。使用螺纹搅拌针在1200 rpm、70 mm/min工艺下获得的接头抗拉强度与延伸率最高,分别为235 MPa、6%;焊缝横截面上硬度分布呈现“W”形状,硬度最低值出现在焊缝两侧热影响区附近。
The friction stir welding(FSW)joints of dissimilar magnesium alloys AZ40M/AZ61A were fabricated with different process parameters.Stereo microscope,optical microscope,scanning electron microscope,microhardness tester and universal testing machine were applied to study the macro morphology,microstructures,mechanical properties and fracture pattern of FSW joints,respectively.The results show that the defect-free joints can be fabricated by the screw threaded tapered pin,however,there are voids and tunnel type defects in the nugget of joints finished by the non-screw threaded tapered pin.The fine exquiaxed grains were formed in the nugget of FSW joints because of dynamic recrystallization.Meanwhile,the grain size changed along the plate thickness direction due to the different heat input.The tensile strength and elongation of the joints fabricated by the threaded tapered pin at 1200 rpm and 70 mm/min were the highest,235 MPa and 6%,respectively.The microhardness profile presents“W”shape along cross-section of the joints and the lowest microhardness value was near heat affected zone.
作者
崔成武
曾惠林
王斌
周培山
王良
CUI Chengwu;ZENG Huilin;WANG Bin;ZHOU Peishan;WANG Liang(China Petroleum Pipeline Research Institute Co.,Ltd.,Langfang 065000,China;Southwest Petroleum University,Chengdu 610500,China;School of Engineering,Southwest Petroleum University,Nanchong 637001,China)
出处
《石油工程建设》
2021年第S01期51-56,共6页
Petroleum Engineering Construction
关键词
异种镁合金
搅拌摩擦焊
焊接接头
显微组织
力学性能
dissimilar magnesium alloy
friction stir welding
welded joints
microstructure
mechanical properties
