Numerical and Experimental Investigation on Hot Backward Extrusion Process of Mg-Gd-Y-Zn-Zr Magnesium Alloy

2014 ◽  
Vol 788 ◽  
pp. 127-133 ◽  
Author(s):  
Zhi Wen Shao ◽  
Xiu Rong Zhu ◽  
Jun Wang ◽  
Rong Wang ◽  
Yong Dong Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Hot Extrusion ◽  
Element Model ◽  
Extrusion Process ◽  
Tensile Yield Strength ◽  
Secondary Phases ◽  
Rigid Plastic ◽  
Backward Extrusion ◽  
The Matrix

The hot backward extrusion process of the Mg-Gd-Y-Zn-Zr magnesium alloy was investigated by both numerical simulation and experiments. An axisymmetric 2D rigid-plastic finite element model (FEM) was established to simulate the material flow during the extrusion process. The shapes of the dies were optimized in order to avoid severe stress concentration and obtain uniform deformation of the workpiece. After hot extrusion, the microstructures of the alloys were obviously refined, and the secondary phases which included many long-period stacking order (LPSO) phases precipitated in the matrix. The optimal comprehensive mechanical properties of the alloy have been obtained after extrusion and ageing at 200°C for 48h with the ultimate tensile strength of 434MPa, tensile yield strength of 375MPa and elongation of 4.5%, respectively. The good mechanical properties were mainly attributed to the fine microstructures and numerous precipitates in the matrix.

Effects of Hot Extrusion and Aging on Microstructure and Mechanical Properties of Mg-Zn-Si-Ca Magnesium Alloy

2013 ◽  
Vol 668 ◽  
pp. 823-829 ◽  
Author(s):  
Xiu Qing Zhang ◽  
Ge Chen ◽  
Yang Wang ◽  
Min Yu Han
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Ultimate Tensile Strength ◽  
Cast Alloy ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Extrusion Ratio ◽  
Deformation Ability

Homogenized magnesium alloy Mg-6Zn-Si-0.25Ca has been hot-extruded and then aging treated for improving the magnesium alloy plastic deformation ability and promoting applications of magnesium alloys. In the hot extrusion process, the influences of extrusion parameters for microstructures and mechanical properties of Mg-6Zn-Si-0.25Ca magnesium alloy were investigated. The results show that dynamic recrystallization occurred during hot extrusion. Compared with as-cast alloy, the grains are fined remarkably, and the mechanical properties are enhanced obviously. Twin crystals appeared in grains after hot extrusion, with the extrusion temperature rising, twin crystal structures has been reduced. Aging further increased the mechanical properties of the estruded alloy. The ultimate tensile strength of Mg-6Zn-Si-0.25Ca alloy is about 385 MPa and the elongation is about 11% when extruded at 320°C(extrusion ratio is 10) and aged at 190°C for 8h.

Tailoring the mechanical properties of Mg–Zn magnesium alloy by calcium addition and hot extrusion process

2020 ◽  
Vol 774 ◽  
pp. 138929 ◽  
Author(s):  
Z. Zareian ◽  
M. Emamy ◽  
M. Malekan ◽  
H. Mirzadeh ◽  
W.J. Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Calcium Addition

Effect of Extrusion Parameters on Mechanical Properties of Al6061-Ni-P Coated SiC Composites

2013 ◽  
Author(s):  
Ramesh Chinnakurli Suryanarayana ◽  
Sikhakolli Ramakrishna ◽  
Ummar Khan Attaullah ◽  
Smitha Hanumantha Badnur ◽  
Kumar Saheb
Keyword(s):  
Mechanical Properties ◽  
Load Transfer ◽  
Hot Extrusion ◽  
Matrix Alloy ◽  
Extrusion Process ◽  
Systematic Investigation ◽  
Strength Properties ◽  
Industrial Applications ◽  
The Matrix ◽  
Sic Composites

Extrusion of metal matrix composites (MMCs) is a very challenging one where in the bond between the reinforcement and the matrix alloy is crucial in getting high quality extrusions for industrial applications. In recent years researchers are focusing on developing aluminium based composites with metallic coated reinforcement to achieve good interfacial bonds to ensure smooth load transfer from the matrix on to reinforcement. However no information is available as regards hot extrusion of metallic coated reinforced MMCs. In the light of the above, the present work focuses on a systematic investigation on effect of extrusion process parameters on mechanical properties of Al6061-Ni-P coated SiC composites. From the investigation, it is observed that hardness, yield and ultimate strength of Al2014-SiC (Both uncoated and Ni-P coated) composites are higher when compared with the matrix alloy for all the extrusion ratios studied (4:1,5:1,10:1,15.5:1) at a given extrusion temperature. However, the ductility of composites decreases with increase in extrusion ratios. Further, heat treatment has a significant effect on the studied mechanical properties. Increase in extrusion temperatures at a given extrusion ratio has resulted in decrease in hardness and strength properties of both matrix alloy and developed composites.

Effect of Distance between Passes in Friction Stir Processing of Magnesium Alloy

2012 ◽  
Vol 585 ◽  
pp. 397-401 ◽  
Author(s):  
M. Govindaraju ◽  
K. Rao Prasad ◽  
Uday Chakkingal ◽  
K. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Friction Stir Processing ◽  
Developmental Studies ◽  
Secondary Phases ◽  
Friction Stir ◽  
Processed Material ◽  
The Matrix ◽  
Cast Alloys ◽  
Tool Pin

Friction stir processing is applied for property improvement of cast alloys for last two decades and many developmental studies were carried out in this topic on various alloys. In the current work, friction stir processing was carried out on rare earth containing magnesium alloy AE42. This alloy was specially developed for automobile application as it has better creep resistance than commercial magnesium alloys. Multi-pass Friction Stir Processing was carried out with varying the distance between passes from 0.5 mm to 2.5 mm using 12 mm shoulder diameter tool. Pin was with conical (tapered) and flat configurations with 3 mm height. After processing, the resultant mechanical and metallurgical properties were evaluated. Microstructure was refined to 5 micron and the secondary phases were made in to tiny pieces of 0.5-1 micron and evenly distributed in the matrix. Continuous network of grain boundary which is reason for poor mechanical properties was eliminated. Mechanical properties were improved by 30%. The variation of mechanical properties of processed material with respect to variation of distance between passes was negligible from 1 mm to 1.5 mm for flat pin tool.

Study on the Mechanical Properties of AZ31 Magnesium Alloy Products Under Hot Extrusion Process

2006 ◽  
Author(s):  
Su-Hai Hsiang ◽  
Yi-Wei Lin
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Process Parameters ◽  
Heating Temperature ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Molybdenum Disulphide ◽  
Speed Method

Magnesium alloy parts have the merits of low specific gravity, high specific strength, electromagnetic wave-proof shelter, and recyclability; therefore, it has been extensively applied to 3C and car industries. However, the processing and forming of magnesium is quite difficult to control due to magnesium’s hexagonal close-packed (HCP) structure, making the slipping face of itself less than the FCC material. Currently, common processing methods of magnesium alloys are die casting, semi-solid forming, and plastic forming. In the employment of a fixed-speed method for extrusion, the extruded sheet had serious defects in the forms of cracks on the surface. Hence, in this research, AZ31 magnesium alloy sheet metals were processed by hot extrusion using a variable speed method. The formability of AZ31 sheets under converging dies was investigated. Three converging dies with semi die angle of 20°, 30°, and 40° were used. Experiments were conducted and analyzed utilizing the Taguchi method. L9 orthogonal array was used to design the experiments under extrusion ratio of 35.9. Four important process parameters considered in this research are the heating temperature of the billet (320°C, 340°C and 360°C), the temperature of the container (300°C, 350°C and 400°C), the initial speed of extrusion (2mm/sec, 3mm/sec and 4mm/sec), and the lubricants (boron nitride, molybdenum disulphide and graphite) applied in the extrusion. The influences of these parameters to the extrusion load and the resulting mechanical properties were investigated. Moreover, the microstructure of the extruded sheets was observed to provide better insight of the formability. As a result, the optimal combinations of the process parameters were determined for the maximum tensile strength.

Effect of Hot Extrusion Process on Microstructure and Properties of Wide and Hollow AZ31 Magnesium Alloy Profiles

2013 ◽  
Vol 710 ◽  
pp. 21-24 ◽  
Author(s):  
Jian Gang Lv ◽  
Gao Feng Quan ◽  
Rui Chun Li ◽  
Chun Yuan Shi ◽  
Ying Bo Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Extrusion Temperature ◽  
Az31 Magnesium Alloy ◽  
Significant Heterogeneity ◽  
Transport Equipment ◽  
Strength And Ductility

According to the profile section of transport equipment, the wide and hollow AZ31 magnesium alloy profiles was self-designed. Extrusion molding performance of the profiles, the law of microstructure and mechanical properties were studied when billets pretreatment and extrusion temperature were changed. The conclusions are as follows: (1) The grains of AZ31 profiles extruded by pre-extrusion billet are smaller and the strength is better, its maximum tensile strength is 280MPa. (2) Other processes being equal, the grains of AZ31 profiles are smaller and strength is higher, but the plastic is bad, when the extrusion temperature is 300°C. However, both strength and ductility of AZ31 profiles are better, when the extrusion temperature is 350°C. (3) Wide and Hollow AZ31 profiles perform significant heterogeneity and anisotropic characteristics on mechanical properties.

Study on Mechanical Properties and Microstructures of Mg-6Zn-2Gd-0.6Zr New Sand-Casting Magnesium Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 651-654 ◽  
Author(s):  
Guang Yu Yang ◽  
Jie Hua Li ◽  
Wan Qi Jie ◽  
Zhong Yu
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Sand Casting ◽  
Secondary Phases ◽  
Elevated Temperature Strength ◽  
Solid Solution Treatment ◽  
The Matrix

A new composition sand-casting magnesium alloy, Mg-6Zn-2Gd-0.6Zr, was developed. It was found that the room temperature mechanical properties of the alloy were superior: b=270MPa, 0.2=175MPa, =8%. Meanwhile, the elevated-temperature strength and creep resistance were significantly improved, comparing with Mg-5Zn-0.6Zr (ZK51) commercial magnesium alloy. The as-cast microstructure of the alloy was mainly consisted of (Mg) matrix, (+Mg3Gd2Zn3+Mg3Gd) eutectic phase, which was distributed along the (Mg) grain boundary with coarse netted shape. After solid-solution treatment and subsequently aging treatment for the alloy, the secondary phases re-precipitated as fine discontinues semi-netted or short rod-like precipitations, also including some fine spherical precipitations in the  matrix, which were responsible for the properties improvement of the alloy.

Properties of AA6061 Aluminum Alloy Reinforced with Different Intermetallics and Ceramics Particles

2006 ◽  
Vol 530-531 ◽  
pp. 255-260
Author(s):  
César Edil da Costa ◽  
Luana de Aguiar ◽  
Vicente Amigó Borras
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Metal Matrix ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Strong Interactions ◽  
Composite Powders ◽  
Good Thermal Stability ◽  
Low Weight ◽  
The Matrix

Aluminum alloys have been increasingly applied as a structural material in composite materials using metal matrix due to their excellent mechanical properties and low weight. The reinforcement are of fundamental importance in composite materials, owing to the their responsibility to support stresses acting on the metal matrix. Therefore, ceramic reinforcements can be replaced by intermetallic components with high mechanical properties and good thermal stability. The intermetallic components react chemically with the matrix, characterized by strong interactions, which makes possible the development of the new families of materials. The composite materials using aluminum reinforced with nickel aluminides and ceramic were developed using techniques based on a combination of powder metallurgy and extrusion processes, which makes possible to obtain more dense materials under lower processing temperatures. The powders of AA6061 and Ni3Al were manually mixed for 30 minutes, with different percentages of intermetallics and ceramics particles, 5 and 10% in weight. The composite powders were submitted to a hot extrusion process for 40 minutes at 540oC, and 385 MPa, with a reduction ratio of 25:1. This process insures extruded composites with a refined structure and a good distribution of the reinforcement particles. The material characterization were performed through structural analysis via scanning electron microscopy; mechanical behavior via tensile and hardening tests; and analysis of the fracture. The results show that the method used is effective to obtain composite materials with improved characteristics.

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