The Influence of Welding Conditions on Mechanical Properties and Microstructural Change of TIG Welded Joint in Extruded Plate AZ31B Mg Alloy

2007 ◽  
Vol 345-346 ◽  
pp. 1441-1444
Author(s):  
Dong Seok Chung ◽  
Y.G. Kim ◽  
S.H. Lee ◽  
B.O. Park ◽  
J.K. Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Welded Joint ◽  
Welding Current ◽  
Microstructural Change ◽  
Mg Alloy ◽  
Second Phase ◽  
Welding Wire ◽  
Joint Region ◽  
Second Phases

This present work investigated the influence of welding conditions, such as welding current, diameter of welding wire on the microstructural change, and mechanical properties of TIG welded joint in extruded AZ31B Mg plate. It was found that a good and sound welded joint was achieved in all welding conditions. The grain size decreased with increasing welding current and decreasing diameter of welding wire. In addition, the second phases were homogeneously distributed in the grain and grain boundary as the welding current and the diameter of the welding wire were decreased. β discontinuous precipitates were observed in the welded joint; this microstructure has not been reported by previous researches investigating AZ31B Mg alloy. The hardness value was affected by the existence state of the second phase and the hardness of the welded joint region was lower than the other regions in welded AZ31B Mg alloy. The strength of the welded joint region was influenced by the grain size and had more than 90 %, compared to that of ASTM standard specification.

Effect of ER5356 Welding Wire on Microstructure and Mechanical Properties of 5083 Aluminum Alloy GTAW Welded Joint

2021 ◽  
pp. 1-9
Author(s):  
DongSheng Zhao ◽  
TianFei Zhang ◽  
LeLe Kong ◽  
DaiFa Long ◽  
YuJun Liu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Welded Joint ◽  
Welding Current ◽  
Travel Speed ◽  
Arc Length ◽  
Welding Wire ◽  
Fracture Elongation ◽  
5083 Aluminum Alloy

Automatic gas tungsten arc welding experiments of 5083 aluminum alloy were completed, to analyze the weld microstructure and mechanical properties. The influences of welding current, travel speed, frequency, and arc length on weld forming and mechanical properties were studied. When the welding current was 160 A, the travel speed was 380 mm/min, the frequency was 100 Hz, the arc length was 4 mm, and the maximum tensile strength of the welded joint was 296.9 MPa, which was 86.8% of the base metal’s tensile strength. The fracture elongation was 7.8%. No porosity was formed in the weld, but there were poor fusion problems. ER5356 welding wire can improve the problem of poor weld fusion and accommodate Mg element vaporization losses. When the wire feeding speed was 1200 mm/min, the tensile strength of the welded joint can be improved to 315.2 MPa, which was 92.2% of the base material’s tensile strength, and the fracture elongation was 8.5%. The tensile specimens fractured in the heat-affected zone. The fracture surface was characterized as plastic fracture.

Microstructure and Mechanical Properties of GTAW Welded Joint of Invar Alloy

2021 ◽  
pp. 1-8
Author(s):  
DongSheng Zhao ◽  
TianFei Zhang ◽  
LiangLiang Wu ◽  
LeLe Kong ◽  
YuJun Liu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Welded Joint ◽  
Welding Current ◽  
Liquid Films ◽  
Invar Alloy ◽  
Welding Parameters ◽  
Welding Seam ◽  
Microstructure And Mechanical Properties

Experiment of automatic gas tungsten arc welding of liquefied natural gas carrier Invar alloy with a thickness of .7 mm was completed, and the welding parameters were optimized, as well as microstructure and mechanical properties of the welded joint were measured and analyzed. The grain size of the area near the weld centerline was small, mainly cellular dendrites, and the grain size on both sides of the weld centerline increased gradually, mainly dendrites, whereas the grain size near fusion line was larger, and there were more columnar crystals. The heat-affected zone was composed of coarse austenite grains. Transgranular cracks were the main cracks in the welding seam. When welding current was 40 A, frequency was 120 Hz, and welding speed was 350 mm/min, tensile strength of the welded joint was 446.9 MPa, which 88.1% of the base metal’s tensile strength and 10.3% of the fracture elongation. The fracture surface of tensile specimens showed typical plastic fracture characteristics, with no obvious crack characteristics, and no eutectic liquid films were observed.

Structure of second phases in TiAl alloys containing Cr and B

1991 ◽  
Vol 49 ◽  
pp. 576-577
Author(s):  
Ernest L. Hall ◽  
Shyh-Chin Huang
Keyword(s):  
Grain Size ◽  
Second Phase ◽  
Structure And Properties ◽  
Tial Alloys ◽  
Second Phases ◽  
Interstitial Elements

Addition of interstitial elements to γ-TiAl alloys is currently being explored as a method for improving the properties of these alloys. Previous work in which a number of interstitial elements were studied showed that boron was particularly effective in refining the grain size in castings, and led to enhanced strength while maintaining reasonable ductility. Other investigators have shown that B in γ-TiAl alloys tends to promote the formation of TiB2 as a second phase. In this study, the microstructure of Bcontaining TiAl alloys was examined in detail in order to describe the mechanism by which B alters the structure and properties of these alloys.

Investigations on Microstructure Evolution and Deformation Behavior of Aged and Ultrafine Grained Al-Zn-Mg Alloy Subjected to Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 253-258
Author(s):  
Wei Ping Hu ◽  
Si Yuan Zhang ◽  
Xiao Yu He ◽  
Zhen Yang Liu ◽  
Rolf Berghammer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Microstructure Evolution ◽  
Deformation Behavior ◽  
Deformation Mechanisms ◽  
Mg Alloy ◽  
Ultrafine Grained

An aged Al-5Zn-1.6Mg alloy with fine η' precipitates was grain refined to ~100 nm grain size by severe plastic deformation (SPD). Microstructure evolution during SPD and mechanical behaviour after SPD of the alloy were characterized by electron microscopy and tensile, compression as well as nanoindentation tests. The influence of η' precipitates on microstructure and mechanical properties of ultrafine grained Al-Zn-Mg alloy is discussed with respect to their effect on dislocation configurations and deformation mechanisms during processing of the alloy.

Internal Stresses in Nanocrystalline Nickel and Nickel-Iron Alloys

2012 ◽  
Vol 706-709 ◽  
pp. 1607-1611 ◽  
Author(s):  
J.D. Giallonardo ◽  
Uwe Erb ◽  
G. Palumbo ◽  
G.A. Botton ◽  
C. Andrei
Keyword(s):  
Grain Size ◽  
Internal Stress ◽  
Structural Difference ◽  
Intrinsic Stress ◽  
Internal Stresses ◽  
Second Phase ◽  
Nickel Iron ◽  
Second Phase Particles ◽  
Second Phases ◽  
Rule Out

Nanocrystalline metals are often produced in a state of stress which can adversely affect certain properties, e.g. corrosion resistance, wear, fatigue strength, etc. This stress is referred to as internal or “intrinsic” stress since it is not directly caused by applied loads. The structural causes of these stresses in nanocrystalline materials are not fully understood and are therefore an area of particular interest. The internal stresses of nanocrystalline Ni and Ni-16wt%Fe were measured and found to increase with the addition of iron. Characterization using HR-TEM revealed no signs of porosity, second phase particles, or a high density of dislocations. Both materials possessed well defined high-angle grain boundaries. The main structural difference between the two materials was found to be grain size and correspondingly, a decrease in grain size resulted in an increase in internal stress which supports the applicability of the coalescence theory. The current study also provides evidence to rule out the effect of voids (or porosity), dislocations, and second phases as possible causes of internal stress.

Effects of Welding Wire Composition on Microstructure and Mechanical Properties of Welded Joint in Al-Mg-Si Alloy

2022 ◽  
Vol 905 ◽  
pp. 44-50
Author(s):  
Li Wang ◽  
Ya Ya Zheng ◽  
Shi Hu Hu
Keyword(s):  
Mechanical Properties ◽  
Fusion Zone ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Weld Zone ◽  
Xrd Analysis ◽  
Metallographic Analysis ◽  
Strengthening Effect ◽  
Welding Wire ◽  
Microstructure And Mechanical Properties

The effects of welding wire composition on microstructure and mechanical properties of welded joint in Al-Mg-Si alloy were studied by electrochemical test, X-ray diffraction (XRD) analysis and metallographic analysis. The results show that the weld zone is composed of coarse columnar dendrites and fine equated grains. Recrystallized grains are observed in the fusion zone, and the microstructure in the heat affected zone is coarsened by welding heat. The hardness curve of welded joint is like W-shaped, the highest hardness point appears near the fusion zone, and the lowest hardness point is in the heat affected zone. The main second phases of welded joints are: matrix α-Al, Mg2Si, AlMnSi, elemental Si and SiO2. The addition of rare earth in welding wire can refine the grain in weld zone obviously, produce fine grain strengthening effect, and improve the electrochemical performance of weld.

scholarly journals Effect of Zn Content on the Microstructure and Mechanical Properties of Mg–Al–Sn–Mn Alloys

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3102
Author(s):  
Tianshuo Zhao ◽  
Yaobo Hu ◽  
Fusheng Pan ◽  
Bing He ◽  
Maosheng Guan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Dendritic Structure ◽  
Second Phase ◽  
Microstructure And Mechanical Properties ◽  
Zn Content ◽  
Dislocation Movement ◽  
Cast Alloys ◽  
Complete Recrystallization ◽  
Second Phases

High performance Mg–6Al–3Sn–0.25Mn–xZn alloys (x = 0, 0.5, 1.0, 1.5, and 2.0 wt %) without rare earth were designed. The effects of different Zn contents on the microstructure and mechanical properties were systematically investigated. The addition of Zn obviously refines the as-cast alloys dendritic structure because of the increase in the number in the second phase. For the as-extruded alloys, an appropriate amount of Zn promotes complete recrystallization, thus increasing the grain size. As the Zn content increases, the texture gradually evolves into a typical strong basal texture, which means that the basal slip is difficult to initiate. Meanwhile, the addition of Zn promotes the precipitation of small-sized second phases, which can hinder the dislocation movement. The combination of texture strengthening and precipitation strengthening is the main reason for the improvement of alloys’ strength.

Effect of Nd Content and Heat Treatment on Microstructure and Mechanical Properties of Mg-Zn-Nd Alloy

2017 ◽  
Vol 898 ◽  
pp. 124-130 ◽  
Author(s):  
Shu Min Xu ◽  
Xin Ying Teng ◽  
Xing Jing Ge ◽  
Jin Yang Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Cast Alloy ◽  
Second Phase ◽  
Casting Method ◽  
Magnesium Matrix ◽  
Microstructure And Mechanical Properties

In this paper, the microstructure and mechanical properties of the as-cast and heat treatment of Mg-Zn-Nd alloy was investigated. The alloy was manufactured by a conventional casting method, and then subjected to a heat treatment. The results showed that the microstructure of as-cast alloy was comprised of α-Mg matrix and Mg12Nd phase. With increase of Nd content, the grain size gradually decreased from 25.38 μm to 9.82 μm. The ultimate tensile strength and elongation at room temperature of the Mg94Zn2Nd4 alloy can be reached to 219.63 MPa and 5.31%. After heat treatment, part of the second phase dissolved into the magnesium matrix and the grain size became a little larger than that of the as-cast. The ultimate tensile strength was declined by about 2.5%, and the elongation was increased to 5.47%.

Effects of Pulsed Magnetic Field on the Microstructure and Mechanical Properties of Mg97Y2Zn1 Alloy

2014 ◽  
Vol 1004-1005 ◽  
pp. 123-126 ◽  
Author(s):  
Jian Yin ◽  
Xiu Jun Ma ◽  
Jun Ping Yao ◽  
Zhi Jian Zhou
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Grain Size ◽  
Volume Fraction ◽  
Pulsed Magnetic Field ◽  
Second Phase ◽  
Microstructure And Mechanical Properties ◽  
Magnetic Field Treatment ◽  
Semi Solid ◽  
Strength And Plasticity

Effect of pulsed magnetic field treatment on the microstructure and mechanical properties of Mg97Y2Zn1 alloy has been investigated. When the pulsed magnetic field is applied on the alloy in semi-solid state, the α-Mg was modified from developed dendrite to fine rosette, resulting in a refined solidification microstructure with the grain size decreased from 4 mm to 0.5 mm. The volume fraction of the second phase ( X phase) increased by about 10 %. The yield strength, fracture strength and plasticity were improved by 21 MPa, 38 MPa and 2.4 %, respectively. The improvement of mechanical properties was attributed to the refined grain size and increased volume fraction of X phase.

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