Effect of CaO Content on Yb: YAG Disk Laser Weldability of AZ31 Mg Alloy

2014 ◽  
Vol 804 ◽  
pp. 31-34 ◽  
Author(s):  
Min Jung Kang ◽  
Cheol Hee Kim
Keyword(s):  
Mechanical Properties ◽  
Specific Gravity ◽  
Laser Welding ◽  
Oxidation Resistance ◽  
Magnesium Alloys ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Weld Strength ◽  
Shielding Gas ◽  
Az31 Mg Alloy

Magnesium alloys have recently attracted increased attention as structural materials owing to their low specific gravity. However, they must typically be casted, formed, melted, and even heated under a protective shielding gas to prevent them from oxidizing and igniting. So-called “ECO-Mg” alloys have recently been developed by adding CaO to conventional Mg alloys. ECO-Mg alloys exhibit higher oxidation resistance during melting and superior castability, even when beryllium is not added or toxic protective gasses such as SF6are not used. We laser-welded AZ31 Mg alloys with various CaO contents and examined the mechanical properties of the welds. Increasing the CaO content in the AZ31 increased the burning resistance of the ECO-Mg alloys, thereby suppressing plume generation during laser welding; thus the ECO-Mg alloy welds could be fully penetrated faster than conventional Mg alloy welds. The weld strength also increased with increasing CaO content in the AZ31 because the CaO refined the grains.

Development of Environment-Friendly CaO Added AZ31 Mg Alloy

2007 ◽  
Vol 124-126 ◽  
pp. 1481-1484 ◽  
Author(s):  
Jin Kyu Lee ◽  
Young Ok Yoon ◽  
Shae K. Kim
Keyword(s):  
Mechanical Properties ◽  
Ignition Temperature ◽  
Sulfur Hexafluoride ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Environment Friendly ◽  
Hfc 134A ◽  
Az31 Mg Alloy ◽  
Protective Cover ◽  
Oxidation Behaviors

Molten Mg alloys burn rapidly in air if not protected. In order to handle molten Mg safely, the molten metal should be protected from oxidation by covering the surface with flux or protective gases. Sulfur hexafluoride (SF6) gas is widely used for Mg alloy as a cover gas and has proved to be a successful inhibitor. However, the use of SF6 gas is limited because of its high cost and its significant impact on global warming potential (GWP). Therefore, SF6 gas is being replaced by alternative protection gases such as tetrafluoro ethane (HFC-134a) and 3M NovecTM 612. These gases are less expensive and have lower GWP, compared with SF6 gas. Recent studies show that there has been another attempt by adding CaO into Mg alloys to manufacture CaO added AZ31Mg alloy in terms of increasing ignition temperature and reducing protective cover gas amount during melting and casting. This paper discusses effect of CaO on ignition and oxidation behaviors of AZ31 Mg alloy as well as on surface roughness and mechanical properties of AZ31 Mg alloy extruded bars.

scholarly journals Fabrication of hydroxyapatite coatings on AZ31 Mg alloy by micro-arc oxidation coupled with sol–gel treatment

RSC Advances ◽  
2018 ◽  
Vol 8 (22) ◽  
pp. 12368-12375 ◽  
Author(s):  
Hui Tang ◽  
Wei Tao ◽  
Chao Wang ◽  
Huilong Yu
Keyword(s):  
Mechanical Properties ◽  
Sol Gel ◽  
Orthopedic Implants ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Hydroxyapatite Coatings ◽  
Az31 Mg Alloy ◽  
Gel Treatment ◽  
Micro Arc Oxidation

Magnesium (Mg) alloys, can potentially be used as biodegradable orthopedic implants because of their biodegradability and good mechanical properties.

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.

Microstructure and mechanical properties of AZ31 Mg alloy produced by a new compound extrusion technique

2018 ◽  
Vol 60 (10) ◽  
pp. 1021-1025 ◽  
Author(s):  
Liwei Lu ◽  
Zhenru Yin ◽  
Jun Zhao ◽  
Dongfeng Shi ◽  
Chuming Li
Keyword(s):  
Mechanical Properties ◽  
Mg Alloy ◽  
Microstructure And Mechanical Properties ◽  
Az31 Mg Alloy

Effect of Rolling Conditions on Microstructure and Mechanical Properties of AZ31 Mg Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 529-532
Author(s):  
Tae Kwon Ha ◽  
Hwan Jin Sung ◽  
Woo Jin Park ◽  
Sang Ho Ahn
Keyword(s):  
Mechanical Properties ◽  
Uniform Elongation ◽  
Warm Rolling ◽  
Thickness Reduction ◽  
Mg Alloy ◽  
Roll Speed ◽  
Single Pass ◽  
Microstructure And Mechanical Properties ◽  
Roll Temperature ◽  
Az31 Mg Alloy

The effect of warm rolling under various conditions on the microstructure and mechanical property was investigated using an AZ31 Mg alloy sheet. Several processing parameters such as initial thickness, thickness reduction by a single pass rolling, rolling temperature, roll speed, and roll temperature were varied to elicit an optimum condition for the warm rolling process of AZ31 Mg alloy. Microstructure and mechanical properties were measured for specimens subjected to rolling experiments of various conditions. Warm rolling of 30% thickness reduction per pass was possible without any side-crack at temperatures as low as 200oC under the roll speed of 30 m/min. The initial microstructure before rolling was the mixed one consisting of partially recrystallized and cast structures. Grain refinement was found to occur actively during the warm rolling, producing a very fine grain size of 7 µm after 50% reduction in single pass rolling at 200oC. Yield strength of 204MPa, tensile strength of 330MPa and uniform elongation of 32% have been obtained in warm rolled sheets.

Friction Stir Welding of Dissimilar Formed Mg Alloys (AZ31/AZ91)

2005 ◽  
Vol 486-487 ◽  
pp. 249-252 ◽  
Author(s):  
Chang Yong Lee ◽  
Won Bae Lee ◽  
Yun Mo Yeon ◽  
Seung Boo Jung
Keyword(s):  
Friction Stir Welding ◽  
Dynamic Recrystallization ◽  
Tensile Test ◽  
Intermetallic Compounds ◽  
Grain Growth ◽  
Weld Zone ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Friction Stir ◽  
Az31 Mg Alloy

Friction stir welding of dissimilar formed Mg alloys(AZ31/AZ91) was successfully carried out at the limited welding conditions. In a sound joint, SZ was mainly consisted of AZ31 Mg alloy which was located the retreating side. Dynamic recrystallization and grain growth occurred and β intermetallic compounds of AZ 91 Mg alloy was not observed in SZ. BM had a higher hardness than that of the weld zone. The fracture location was not weld zone but BM of the AZ91 Mg alloy in tensile test.

Influence of CO2-Ar Mixtures as Shielding Gas on Laser Welding of Al-Mg Alloys

2013 ◽  
Vol 44 (13) ◽  
pp. 5711-5723 ◽  
Author(s):  
Zouhair Boukha ◽  
José María Sánchez-Amaya ◽  
Leandro González-Rovira ◽  
Eloy Del Rio ◽  
Ginesa Blanco ◽  
...  
Keyword(s):  
Laser Welding ◽  
Mg Alloys ◽  
Shielding Gas ◽  
Al Mg Alloys

Improving the Mechanical Properties of AZ31 Mg Alloy by High Ratio Extrusion

2006 ◽  
Vol 503-504 ◽  
pp. 865-870 ◽  
Author(s):  
Yongjun Chen ◽  
Qu Dong Wang ◽  
Jianguo Peng ◽  
Chun Quan Zhai
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
High Ratio ◽  
Extrusion Ratio ◽  
Mg Alloy ◽  
Fine Grained ◽  
Az31 Mg Alloy ◽  
Industry Applications ◽  
One Step ◽  
The One

Experiments were conducted both to evaluate the potential for grain refinement, the subsequent mechanical properties at room temperature in samples of AZ31 Mg alloy and also to investigate the relationship between one-step and two-step high ratio extrusion (HRE). The one-step HRE was undertaken using a high extrusion ratio of 70:1 at 250, 300 and 350°C. And the two-step HRE was conducted with an extrusion ratio of 7 for the first step at 250, 300 and 350°C, followed by a second-step extrusion with an extrusion ratio of 10 at 250, 300 and 350°C. The initial grain size in the AZ31 ingot was 100μm and that after one-step HRE became similar to 5μm, after two-step HRE at 250, 300 and 350°C were 2, 4, 7μm, respectively, resulting in superior mechanical properties at ambient temperature. The microstructure of two-step HRE was finer and uniformer than that of one-step HRE and the strength of one-step and two-step HRE were similar, moreover, the elongation of one-step HRE was improved markedly than that of two-step HRE. Dynamic recrystallization and adjacent grain broking during HRE is introduced to explain the effects of one-step and two-step HRE on the microstructure and mechanical properties of AZ31 Mg alloy. The current results imply that the simple HRE method might be a feasible processing method for industry applications, and the multiply steps extrusion are effective to fabricate high strength of fine grained hcp metals.

Correlation between Zirconium Addition and Compressive Properties of AZ31 Mg Alloy Foams

2011 ◽  
Vol 121-126 ◽  
pp. 75-79
Author(s):  
Bo Young Hur ◽  
Rui Zhao
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Mg Alloy ◽  
Compressive Properties ◽  
Absorption Properties ◽  
Compression Behavior ◽  
Foaming Agent ◽  
Az31 Mg Alloy ◽  
Absorption Characteristics ◽  
Zirconium Addition

The compressive behaviors of AZ31-Zr foams using Ca particles as thickening agent and CaCO3 powder as foaming agent were investigated in this study. The porosity was about 48.7%~72.9%, pore size was between 0.43~0.97 mm, and homogenous pore structures were obtained. Mechanical properties of AZ31 Mg alloy foams were investigated by means of UTM. The cellular AZ31 Mg foams possess superior comprehensive mechanical properties. The energy absorption characteristics and the effects of compression behavior on the energy absorption properties for the cellular AZ31 Mg foams have been investigated and discussed. The results show that with the addition of Zr, the Mg alloy foam has the highest energy absorption value of 16.26 MJ/m3 and the hardness value of 81.8 HV, which is much higher than that of the foams fabricated without Zr.

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