scholarly journals Effects of Filler Wires on the Microstructure and Mechanical Properties of 2195-T6 Al-Li Alloy Spray Formed by TIG Welding

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3559 ◽  
Author(s):  
Yuhui Zhang ◽  
Huan Li ◽  
Chuanguang Luo ◽  
Lijun Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Grain Boundaries ◽  
Fracture Mode ◽  
Weld Joint ◽  
Space Vehicle ◽  
Fusion Line ◽  
Filler Wire ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties

The main purpose of this work was to investigate the microstructure and mechanical properties of spray-formed 2195-T6 Al-Li alloy welding joints produced by tungsten inert gas (TIG) with Al-Cu and Al-Si-Cu filler wires, so that they can be better used in space vehicle tanks. The porosity analysis indicates that the porosity area of the weld seam with the Al-Si-Cu filler wire is approximately 7.989 times larger than that of the Al-Cu filler wire. Furthermore, the microstructure and microhardness results indicate that the Al/Cu eutectic near the fusion line distributes more at the grain boundaries, while more dispersed Al2Cu phase is found inside the grain, which improves the strength of the joint when using Al-Cu filler wire. However, when using the Al-Si-Cu filler wire, more Si, Cu, and Ti elements are segregated at the grain boundaries, forming a brittle-hard network Al/Cu/Ti eutectic, which reduces the performance of the joint. Additionally, the tensile strength and elongation of the weld joint are about 68.6% and 89.9% of the base metal (BM) when using the Al-Cu filler wire, and can approach the level of friction stir welding (FSW). However, the tensile strength and elongation are only about 56.8% and 39.9%, respectively, of the BM in the weld joint when using the Al-Si-Cu filler wire. Lastly, the fractures both occur on the fusion line and the fracture morphology of the weld joint shows that it is a mixed fracture mode dominated by plastic fracture when using Al-Cu filler wire, while it is mainly a quasi-cleavage fracture mode when using Al-Si-Cu filler wire. Therefore, the joint strength when using Al-Si-Cu filler wire with high strength matching is not as good as that of Al-Cu filler wire with low strength matching.

scholarly journals The Effect of Process Parameters on the Microstructure and Mechanical Properties of AW5083 Aluminum Laser Weld Joints

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1443 ◽  
Author(s):  
Maroš Vyskoč ◽  
Miroslav Sahul ◽  
Mária Dománková ◽  
Peter Jurči ◽  
Martin Sahul ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Process Parameters ◽  
Flow Rate ◽  
Weld Joint ◽  
Gas Flow ◽  
Filler Wire ◽  
Shielding Gas ◽  
Gas Flow Rate ◽  
Weld Joints

In this article, the effect of process parameters on the microstructure and mechanical properties of AW5083 aluminum alloy weld joints welded by a disk laser were studied. Butt welds were produced using 5087 (AlMg4.5MnZr) filler wire, with a diameter of 1.2 mm, and were protected from the ambient atmosphere by a mixture of argon and 30 vol.% of helium (Aluline He30). The widest weld joint (4.69 mm) and the highest tensile strength (309 MPa) were observed when a 30 L/min shielding gas flow rate was used. Conversely, the narrowest weld joint (4.15 mm) and the lowest tensile strength (160 MPa) were found when no shielding gas was used. The lowest average microhardness (55.4 HV0.1) was recorded when a 30 L/min shielding gas flow rate was used. The highest average microhardness (63.9 HV0.1) was observed when no shielding gas was used. In addition to the intermetallic compounds, β-Al3Mg2 and γ-Al12Mg17, in the inter-dendritic areas of the fusion zone (FZ), Al49Mg32, which has an irregular shape, was recorded. The application of the filler wire, which contains zirconium, resulted in grain refinement in the fusion zone. The protected weld joint was characterized by a ductile fracture in the base material (BM). A brittle fracture of the unshielded weld joint was caused by the presence of Al2O3 particles. The research results show that we achieved the optimal welding parameters, because no cracks and pores were present in the shielded weld metal (WM).

Microstructure and Mechanical Properties of TiB2/ Al-Si Composites Fabricated by TIG Wire and Arc Additive Manufacturing

2019 ◽  
Vol 944 ◽  
pp. 64-72
Author(s):  
Qing Feng Yang ◽  
Cun Juan Xia ◽  
Ya Qi Deng
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Yield Strength ◽  
Filler Wire ◽  
T6 Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
Before And After

Bulky sample was made by using TIG wire and arc additive manufacturing (WAAM) technology, in which Ф1.6 mm filler wire of in-situ TiB2/Al-Si composites was selected as deposition metal, following by T6 heat treatment. The microstructure and mechanical properties of the bulky sample before and after heat treatment were analyzed. Experimental results showed that the texture of the original samples parallel to the weld direction and perpendicular to the weld direction was similar consisting of columnar dendrites and equiaxed crystals. After T6 heat treatment, the hardness of the sample was increased to 115.85 HV from 62.83 HV, the yield strength of the sample was 273.33 MPa, the average tensile strength was 347.33 MPa, and the average elongation after fracture was 7.96%. Although pore defects existed in the fracture, yet the fracture of the sample was ductile fracture.

scholarly journals Improving mechanical properties of ZK60 magnesium alloy by cryogenic treatment before hot extrusion

2020 ◽  
Vol 39 (1) ◽  
pp. 200-208
Author(s):  
Tao Lin ◽  
Ji-Xue Zhou ◽  
Cai-Nian Jing ◽  
Yun-Teng Liu ◽  
Lin-Lin Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Grain Boundaries ◽  
Cryogenic Treatment ◽  
Hot Extrusion ◽  
Microstructure And Mechanical Properties ◽  
Zk60 Alloy ◽  
Nonferrous Alloys ◽  
Zk60 Magnesium Alloy

AbstractFew studies of cryogenic treatment were focused on nonferrous alloys, such as magnesium alloy. In this work, the effect of cryogenic treatment (77 K) before extrusion on microstructure and mechanical properties of ZK60 alloy was investigated. The results showed that many fine G.P. zones were formed during the cryogenic treatment and then grew to short fine {\beta }_{1}^{^{\prime} } precipitates when heating before extrusion. These precipitates pinned dynamic recrystallized grain boundaries in the subsequent extrusion, resulting in fine gains and dispersed spherical precipitates. By the cryogenic treatment before extrusion, the extruded ZK60 alloy showed good tensile strength and elongation balance. Especially, elongation was improved by 29%.

Microstructure and Mechanical Properties of 3-Wire Electroslag Welded (ESW) High-Speed Pearlitic Rail Steel Joint

2020 ◽  
Vol 837 ◽  
pp. 28-34
Author(s):  
Adnan Raza Khan ◽  
Sheng Fu Yu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Colony Size ◽  
High Speed ◽  
Fusion Line ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Microstructure And Mechanical Properties ◽  
Pearlite Colony

The present paper aims at utilizing the 3-wire electroslag welding (ESW) to join high-speed pearlitic rail steels where microstructure and mechanical properties were investigated. The welded joint has produced an improved fracture force of 1396KN. WM was consisted of ferrite and pearlite having hardness of 27HRC, tensile strength of 748MPa and toughness of 12J, successively. HAZ was composed of pro-eutectoid ferrite and pearlite, where austenite grain size and pearlite colony size were reduced by moving away from the fusion line. In HAZ, near to the fusion line, the austenite grain size was 143±19μm, pearlite colony size was 52±9μm and pearlite interlamellar spacing was 90±27nm, which has produced hardness of 43.5HRC, tensile strength of 1228MPa, and toughness of 8J, successively. The entire investigation concludes that 3-wire ESW is an optimum and viable method, which has provided fine pearlite microstructure along with improved hardness and tensile strength.

scholarly journals The Effect of Processing Pass on the Microstructure and Mechanical Properties of a Friction Stir Processed As-Cast Mg-6 wt % Sn Alloy

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 906 ◽  
Author(s):  
Yang Zhang ◽  
Xiaoyang Chen ◽  
Xiyun Qin ◽  
Feilong Li ◽  
Yalin Lu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Grain Refinement ◽  
Dynamic Precipitation ◽  
Basal Texture ◽  
Continuous Increase ◽  
Phase Dynamic ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Mg2sn Phase

In this study, as-cast Mg-6 wt % Sn alloy is subjected to one-pass and two-pass friction stir processing (FSP). The effect of processing pass on microstructure and mechanical properties of FSP Mg-6Sn alloy is investigated. It is found that one-pass FSP leads to the breakage and partial dissolution of the Mg2Sn phase in the stir zone (SZ) and two-pass FSP leads to the further dissolution and dynamic precipitation of the Mg2Sn phase. Dynamic recrystallization (DRX) takes place in the SZ of an Mg-6Sn alloy undergoing FSP. Compared to one-pass FSP, two-pass FSP brings about further grain refinement in the SZ. A strong {0001} basal texture is developed in the SZ of a Mg-6Sn alloy from FSP and the change of the sample region or processing pass has little influence on the texture. Compared to an as-cast Mg-6Sn sample, one-pass FSP brings about significant improvement in mechanical properties. Two-pass FSP leads to the further increase in yield strength (YS) and ultimate tensile strength (UTS) but elongation (EL) is reduced. The continuous increase in strength is attributed to the grain refinement and the dissolution and dynamic precipitation of Mg2Sn phase achieved by FSP.

scholarly journals Influence of Welding Speed on Microstructure and Mechanical Properties of 5251 Aluminum Alloy Joints Fabricated by Self-Reacting Friction Stir Welding

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6178
Author(s):  
Shikang Gao ◽  
Li Zhou ◽  
Guangda Sun ◽  
Huihui Zhao ◽  
Xiaolong Chu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Welding Speed ◽  
Fracture Characteristics ◽  
Void Defect ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
Microstructure And Mechanical Properties ◽  
Quality Surface

In the present study, 8 mm-thick 5251 aluminum alloy was self-reacting friction stir welded (SRFSW) employing an optimized friction stir tool to analyze the effect of welding speed from 150 to 450 mm/min on the microstructure and mechanical properties at a constant rotation speed of 400 rpm. The results indicated that high-quality surface finish and defect-free joints were successfully obtained under suitable process parameters. The microhardness distribution profiles on the transverse section of joint exhibited a typical “W” pattern. The lowest hardness values located at the heat-affected zone (HAZ) and the width of the softened region decreased with increasing welding speed. The tensile strength significantly decreased due to the void defect, which showed mixed fracture characteristics induced by the decreasing welding speed. The average tensile strength and elongation achieved by the SRFSW process were 242.61 MPa and 8.3% with optimal welding conditions, and the fracture surface exhibited a typical toughness fracture mode.

Microstructure and Mechanical Properties of Friction Stir Welded Al-Zn-Mg-Cu Alloy

2014 ◽  
Vol 628 ◽  
pp. 7-11
Author(s):  
Sheng Dan Liu ◽  
Yun Dai ◽  
Yu Long Wu ◽  
Bin Chen ◽  
Xin Ming Zhang
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Base Material ◽  
Optical Microscope ◽  
Alloy Sheet ◽  
Grain Structure ◽  
Hardness Profile ◽  
Friction Stir ◽  
Cu Alloy ◽  
Microstructure And Mechanical Properties

The microstructure and mechanical properties of friction stir welded Al-Zn-Mg-Cu alloy sheet were investigated by means of hardness and tensile tests, optical microscope and scanning electron microscope. The hardness profile of the weld exhibits a W shape with the lowest value in the thermo-mechanically affected zone on the advancing side. The tensile strength and elongation of the weld are about 71% and 72% that of the base material. In the nugget zone, there are a number of fine recrystallized grains and dispersed precipitates at grain boundaries. In the thermo-mechanically affected zone, the grain size is not uniform and there are a number of precipitates at grain boundaries. In the heat affected zone, the grain structure is similar to the base material.

Influence of post welding heat treatment on the microstructure and mechanical properties of friction stir welding joint of AZ31 Mg alloy

2021 ◽  
pp. 095440892199762
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Tensile Failure ◽  
Mg Alloy ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Az31 Mg Alloy

At present, magnesium alloys are extensively used in numerous applications due to their light weight and better characteristics. Welding of magnesium alloys is regarded as one of the most complex phenomena in various industries. The friction stir welding of magnesium alloys has encouraged abundant scientific and industrial interest as it has the potency to form a good quality joint. Post welding heat treatment is an appropriate process to further improve the properties or performance of FSW joints. Therefore, the present work aims to join AZ31 Mg alloy plates by friction stir welding, and microstructural and mechanical properties of the joint have been examined. Furthermore, the consequence of post welding heat treatment on the microstructure and mechanical properties of FSW joint has been evaluated. Tensile strength and elongation of FSW joint were about 145.4 ± 4.9 MPa and 9.5 ± 0.9%, respectively. It was found that post welding heat treatment was beneficial in homogenizing grains and to enhance mechanical properties. Tensile strength and elongation of the joint were improved by 4.74% and 15.78% respectively after PWHT. The highest microhardness of stir zone decreased about 6.84% (73 Hv to 68 Hv) after heat treatment and hardness pattern of weld became relatively smooth. Toughness of PWHT joint was 4.5 ± 0.17 Joules. The mode of tensile failure of as-welded and PWHT joint was ductile.

scholarly journals Microstructure and Mechanical Properties of Friction Stir Processed A356 Cast Al under Air Cooling and Water Cooling

2018 ◽  
Vol 37 (7) ◽  
pp. 693-699
Author(s):  
Xinxin Ai ◽  
Yumei Yue
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Base Material ◽  
Cast Aluminum Alloy ◽  
Air Cooling ◽  
Water Cooling ◽  
Cast Aluminum ◽  
Friction Stir ◽  
Cooling Conditions ◽  
Microstructure And Mechanical Properties

AbstractIn this work, friction stir processing (FSP) was used to modify the microstructure of A356 cast aluminum alloy under air cooling and water cooling conditions. The microstructure and mechanical properties of air cooling and water cooling FSP specimens and their differences were mainly discussed. Results show that the grains can be significantly refined after FSP under both air cooling and water cooling conditions. The water cooling FSP specimen shows much smaller grains than the air cooling FSP specimen due to lower temperature. Similarly, the Si particles of water cooling FSP specimen show much smaller sizes and better distribution. Both the air cooling FSP specimen and water cooling FSP specimen own much higher tensile strength and elongation than A356 base material (BM). In particular, the tensile strength and elongation of water cooling specimen are respectively 231 Mpa and 14.15%, which are equal to 186.3% and 1088.5% of the BM. Furthermore, the microhardness of water cooling FSP specimen is lower than that of the air cooling FSP specimen.

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