共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
The microstructure in the joints of a non-heat-treatable aluminum–magnesium 1565chM alloy sheets fabricated by friction stir welding is studied. The structure near the interface between the base metal and a welded joint is examined. Friction stir welding results in a gradient structure with ultrafine grains at the center of the welded joint. The structure in the welded joint forms by the mechanism resulting in the formation of a layered ultrafine structure due to plastic deformation by shear and rotation of structural fragments. Layers are assumed to form due to the balance between the strain hardening and the softening caused by frictional heating and heat released during deformation. An analogy between the microstructure in the joint fabricated by friction stir welding and the microstructure formed by sliding friction is drawn. 相似文献
3.
Yu. G. Bykov E. O. Fomichev O. S. Kashapov K. A. Kyaramyan 《Russian Metallurgy (Metally)》2017,2017(12):1037-1041
The conditions of electron-beam welding (EBW) of ring samples made of a VT41 alloy are adjusted to produce large welded joints of this alloy for a high-pressure compressor (HPC) of an advanced engine. The problems of quality control of a welded joint, the level of residual stresses in the near-weld zone, the microstructure of the welded joint, and its properties are considered. 相似文献
4.
5.
6.
Microstructure and mechanical properties of Al-Mg-Mn-Zr-Er weld joints filled with Al-Mg-Mn-Zr and Al-Mg-Mn-Zr-Er weld wires 总被引:1,自引:1,他引:0
The Al-Mg-Mn-Zr-Er alloy sheets with a thickness of 4 mm were welded by TIG welding, the microstructures and mechanical properties of Al-Mg-Mn-Zr-Er alloy weld joints filled with F1.6 mm Al-Mg-Mn-Zr and Al-Mg-Mn-Zr-Er welding wires were studied by optical microscopy, scanning electron microscopy, transmission electron microscopy, hardness testing and tensile mechanical properties testing. The result showed that, the tensile strength increased by 57 MPa and the coefficient of weld joint reached 0.8 when Al-Mg-Mn-Zr-Er welding wire was used as filling material. The tensile strength and elongation of weld joint filled with Al-Mg-Mn-Zr-Er welding wire were 19% and 85% higher those that of filled with Al-Mg-Mn-Zr welding wire respectively, which resulted from grain refinement strengthening and dispersion strengthening of Al3Er. 相似文献
7.
因锌合金不易焊接,采用加入焊剂的方法对新型模用锌基合金(ZA合金)进行了TIG焊接。通过金相显微镜、X射线衍射等分析方法对焊接接头组织及焊后残渣采样进行分析,并对焊剂的作用机理进行了初步研究。结果表明:焊接过程中,焊缝表面形成大量氧化物;加入焊剂的主要作用是通过冶金反应清除焊接材料表面的氧化膜,同时向焊缝中过渡Zn。 相似文献
8.
S. H. Chowdhury D. L. Chen S. D. Bhole E. Powidajko D. C. Weckman Y. Zhou 《Metallurgical and Materials Transactions A》2012,43(6):2133-2147
This study was aimed at characterizing microstructural change and evaluating tensile and fatigue properties of fiber laser
welded AZ31B-H24 Mg alloy with special attention to the effect of welding speed. Laser welding led to the formation of equiaxed
dendrites in the fusion zone and columnar dendrites near the fusion zone boundary along with divorced eutectic Mg17Al12 particles and recrystallized grains in the heat-affected zone. The lowest hardness across the weld appeared in the fusion
zone. Although the yield strength, ductility, and fatigue life decreased, the hardening capacity increased after laser welding,
with a joint efficiency reaching about 90 pct. A higher welding speed resulted in a narrower fusion zone, smaller grain size,
higher yield strength, and longer fatigue life, as well as a slightly lower strain-hardening capacity mainly because of the
smaller grain sizes. Tensile fracture occurred in the fusion zone, whereas fatigue failure appeared essentially in between
the heat-affected zone and the fusion zone. Fatigue cracks initiated from the near-surface welding defects and propagated
by the formation of fatigue striations together with secondary cracks. 相似文献
9.
使用3种焊丝ER 5183、ER 5356、ER 5554对6mm 5182-H111铝合金板材进行半自动MIG焊对接试验,通过对焊接接头进行力学性能试验、显微硬度测试及金相组织的观察,探究3种焊丝对5182-H111铝合金组织和性能的影响。结果表明,使用3种焊丝所焊接头中,ER 5183及ER 5356接头抗拉强度均大于ISO 15614-22005要求的焊缝接头系数(1.0),而ER 5554接头焊缝系数仅为0.949;3种焊丝所焊接头硬度均在焊缝区及热影响区有所降低,其中ER 5356所焊接头焊缝强度较其他两种焊丝焊缝区硬度高,为85.5HV;3种焊丝所焊接头组织形貌相近,均存在β(Mg2Al3)强化相,但由于ER 5183与ER 5356焊丝中含有更多的Mg,因此生成了更多的β(Mg2Al3)相,使得焊缝组织更加致密。 相似文献
10.
Jérémie Graneix Jean-Denis Beguin Joël Alexis Talal Masri 《Metallurgical and Materials Transactions B》2017,48(4):2007-2016
The weldability of 1.2 mm thick Haynes 188 alloy sheets by a disk Yb:YAG laser welding was examined. Butt joints were made, and the influence of parameters such as power, size, and shape of the spot, welding speed, and gas flow has been investigated. Based on an iconographic correlation approach, optimum process parameters were determined. Depending on the distribution of the power density (circular or annular), acceptable welds were obtained. Powers greater than 1700 W, welding speeds higher than 3.8 m mm?1, and spot sizes between 160 and 320 μm were needed in the circular (small fiber) configuration. By comparison, the annular (large fiber) configuration required a power as high as 2500 W, and a welding speed less than 3.8 m min?1. The mechanical properties of the welds depended on their shape and microstructure, which in turn depended on the welding conditions. The content of carbides, the proportion of areas consisting of cellular and dendritic substructures, and the size of these substructures were used to explain the welded joint mechanical properties. 相似文献
11.
对加Al质量分数为4%的304、2%的316L不锈钢热轧板材的焊接性能进行了研究。采用手工氩弧焊(TIG)的焊接方法,利用光学显微镜对焊缝的显微组织进行分析,利用电子探针(EMPA)分析焊接母材的元素分布,并对焊接接头进行力学性能测试。组织和力学性能的研究结果表明:含铝304和含铝316L合金热轧板分别选用ER308L,ER316L作为焊接材料,经TIG焊接后,焊缝无裂纹、气孔等缺陷,接头具有良好的强度和塑性,焊接接头力学性能接近于其母材;热影响区组织与母材组织基本一致,焊缝与母材熔合良好,组织良好,加铝304和316L不锈钢具有良好的焊接性能。 相似文献
12.
Optimization of Friction Welding Process Parameters for Joining Carbon Steel and Stainless Steel 总被引:2,自引:0,他引:2
Friction welding is a solid state joining process used extensively currently owing to its advantages such as low heat input, high production efficiency, ease of manufacture, and environment friendliness. Materials difficult to be welded by fusion welding processes can be successfully welded by friction welding. An attempt was made to develop an empirical relationship to predict the tensile strength of friction welded AISI 1040 grade medium carbon steel and AISI 304 austenitic stainless steel, incorporating the process parameters such as friction pressure, forging pressure, friction time and forging time, which have great influence on strength of the joints. Response surface methodology was applied to optimize the friction welding process parameters to attain maximum tensile strength of the joint. The maximum tensile strength of 543 MPa could be obtained for the joints fabricated under the welding conditions of friction pressure of 90 MPa, forging pressure of 90 MPa, friction time of 6 s and forging time of 6 s. 相似文献
13.
针对熔化焊在焊接AA7B04铝合金时易在焊缝中出现孔洞等缺陷,且接头性能下降明显、焊后变形大,以及采用铆接等机械连接方式会增加连接件的重量等问题,采用集成了搅拌摩擦焊末端执行器的KUKA Titan机器人对2 mm厚AA7B04高强铝合金进行了焊接,在转速为800 r·min-1的条件下,研究了焊度对焊接过程中搅拌头3个方向的受力Fx、Fy和Fz的影响.研究发现,Fz受焊速的影响显著,随焊速的增加而降低.利用光学显微镜、透射电子显微镜、拉伸试验、三点弯曲试验和硬度测试等方法,研究了不同焊速下AA7B04铝合金接头的微观组织和力学性能.结果表明:当焊速为100 mm·min-1时,接头的抗拉强度最高为447 MPa,可达母材的80%,且所有接头的正弯和背弯180°均无裂纹;接头横截面的硬度分布呈W型,硬度最低点出现在热力影响区和焊核区的交界处,焊速不同会导致不同的焊接热循环,且随着焊速的增加接头的硬度随之增加;焊核区组织发生了动态再结晶,生成了细小的等轴晶粒,前进侧和后退侧热力影响区的晶粒均发生了明显的变形;前进侧热影响区析出η'相,后退侧热影响区因温度较高析出η'相和尺寸较大的η相. 相似文献
14.
15.
Effects of
surface condition, welding parameters and interlayers on the strength of welded joint of
SiCw/6061Al composite subjected to diffusion welding were studied. High quality
of welded joint of SiCw/6061Al composite was successfully obtained with proper welding
technology. 相似文献
16.
17.
Influence of Post-Laser Welding Heat Treatment on Assembling Performance of Aluminum Alloy Structure
Guillaume Tirand Corinne Arvieu Eric Lacoste Jean-Michel Quenisset 《Metallurgical and Materials Transactions A》2013,44(12):5577-5586
The need to reach the mechanical performance of age hardened Al-Mg-Si (6000 series) base alloy of structures, the assemblies of which are processed by laser welding, has required the efficiency evaluation of age hardening heat treatment performed after welding. It has been established that post-laser aging treatments are not efficient enough to give laser welded assemblies the expected performance of hardened Al base alloy in term of micro-hardness, ultimate tensile strength, and failure deformation. This lack of efficiency has been attributed to insufficient cooling kinetic during laser welding rather than to composition deviation of the bead due to the use of Si rich filler. The interposition of solution heat treatment between welding and aging treatment has been proposed and has shown its efficiency to give the laser welded zone a sufficient strength, similar to that of Al base alloy. 相似文献
18.
A. Venugopal K. Sreekumar V.S. Raja 《Metallurgical and Materials Transactions A》2010,41(12):3151-3160
The stress corrosion cracking (SCC) behavior of AA2219 aluminum alloy in the as-welded (AW) and repair-welded (RW) conditions
was examined and compared with that of the base metal (BM) in 3.5 wt pct NaCl solution using the slow strain rate technique
(SSRT). The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of both BM and welded joints.
The results show that the ductility ratio (ε
NaCl/(ε
air)) of the BM was close to one (0.97) and reduced to 0.9 for the AW joint. This value further reduced to 0.77 after carrying
out one repair welding operation. However, the RW specimen exhibited higher ductility than the single-weld specimens even
in 3.5 wt pct NaCl solution. SSRT results obtained using pre-exposed samples followed by post-test metallographic observations
clearly showed localized pitting corrosion along the partially melted zone (PMZ), signifying that the reduction in ductility
ratio of both the AW and RW joints was more due to mechanical overload failure, caused by the localized corrosion and a consequent
reduction in specimen thickness, than due to SCC. Also, the RW joint exhibited higher ductility than the AW joint both in
air and the environment, although SCC index (SI) for the former is lower than that of the latter. Fractographic examination
of the failed samples, in general, revealed a typical ductile cracking morphology for all the base and welded joints, indicating
the good environmental cracking resistance of this alloy. Microstructural examination and polarization tests further demonstrate
grain boundary melting along the PMZ, and that provided the necessary electrochemical condition for the preferential cracking
on that zone of the weldment. 相似文献
19.
采用新型Al-Mg-Sc-Zr焊丝对含钪Al-Zn-Mg-Zr合金薄板材进行MIG焊,借助显微硬度及拉伸性能测试、OM,SEM,TEM等检测手段对焊接接头的微观组织和性能进行研究。结果表明:焊缝区为典型的铸态组织;热影响区靠近焊缝一侧呈现大量细小等轴晶组织,靠近基材区为纤维状组织和少量再结晶组织;基材区为纤维状组织。焊接接头的显微硬度以焊缝为中心呈近似对称,且中心处硬度值最低;抗拉强度为481 MPa,屈服强度为320MPa,伸长率为10.1%,焊接系数约0.83。同时,焊丝和基材中微量的Sc和Zr元素在合金中形成大量细小且与基体共格的Al3(Sc,Zr)粒子,能显著细化晶粒组织,有效抑制再结晶发生,大大改善焊缝区的力学性能。 相似文献
20.
分别采用J442(/%:≤0.12C、0.3~0.6Mn)、J506(/%:≤0.12C、≤1.6Mn)和J507(/%:≤0.12C、≤1.25Mn)焊条对7 mm SS400钢板(/%:0.18C、0.04Si、0.43Mn、0.022Al、0.002Ca)在热输入6~14 kJ/cm下进行手工电弧焊实验,并通过光学显微镜和显微硬度计观察和测试焊接接头的组织和硬度。结果表明,随焊条合金元素含量的增加,焊缝组织中针状铁素体量增加,当热输入≤10 kJ/cm时,焊接热影响区粗晶尺寸变化不大,当热输入大于10 kJ/cm时,粗晶尺寸明显增大;不同焊接工艺焊接接头的显微硬度均高于母材的显微硬度,没有接头软化现象。 相似文献