Effect of Holding Time on Microstructures of AZ91D Alloy by the Semi-Solid Thixo-Extruded Process

2015 ◽  
Vol 1088 ◽  
pp. 191-194
Author(s):  
Xiao Ping Zheng ◽  
Ze Sheng Ji ◽  
Wei Wen Zhang ◽  
Ming Shao
Keyword(s):  
Mechanical Property ◽  
Particle Size ◽  
Magnesium Alloy ◽  
Shape Factor ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Az91d Alloy ◽  
Az91d Magnesium Alloy ◽  
Semi Solid ◽  
The Relationship

The semi-solid thixo-extruded process of AZ91D magnesium alloy with 9 % plastic deformation was investigated. The effect of isothermal time on the thixo-extruded formability of AZ91D magnesium alloy was analyzed. The relationship between isothermal time and microstructure, mechanical property was also researched. The results showed that with increasing the isothermal time from zero to 60 min on 575 °C, the filling distance was increased firstly and then decreased, the solid volume fraction was decreased firstly and then increased, the tensile strength and elongation were also increased firstly and then decreased. However, the increasing isothermal time would lead to decrease of shape factor but the coarsening of particle size. When the isothermal time was 30 min, the solid volume fraction was lowest and the filling distance was greatly increased obviously.

Studies of Microstructures and Properties of AZ91D Alloy Based on the Rheoforming Process

2015 ◽  
Vol 713-715 ◽  
pp. 2876-2879
Author(s):  
Xiao Ping Zheng ◽  
Ze Sheng Ji ◽  
Wei Wen Zhang ◽  
Ming Shao
Keyword(s):  
Mechanical Property ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Solid Fraction ◽  
Shape Factor ◽  
Holding Time ◽  
Az91d Alloy ◽  
Conventional Casting ◽  
Semi Solid ◽  
The Relationship

The semi-solid rheoforming process of AZ91D alloy with 9 % plastic deformation was investigated. The effect of holding time on the rheoforming formability of AZ91D alloy was analyzed. The relationship between holding time and microstructure, mechanical property was also researched. The results show that with increasing of holding time from 0 to 60 min at 575 °C, the filling distance increases firstly and then decreases, the solid fraction decreases firstly and then increases, the tensile strength and elongation are also increase firstly and then decrease. However, the increasing of holding time would lead to shape factor decreasing but particle coarsening. When holding time is 30 min, the solid fraction is lowest and the filling distance increases greatly. Compared to the conventional casting sample, the tensile strength and elongation of the rheoforming parts increase 43.9 % and 187.5 %, respectively.

Theoretical Analysis of Plastic Forming Process for Semi-Solid Material

2005 ◽  
Vol 488-489 ◽  
pp. 389-392 ◽  
Author(s):  
Hong Yan ◽  
Juchen Xei
Keyword(s):  
Magnesium Alloy ◽  
Upper Bound ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Normal Component ◽  
Solid Material ◽  
Tangential Component ◽  
Forming Process ◽  
Plastic Forming ◽  
Semi Solid

The plastic forming of magnesium alloy is difficult, but the semi-solid material forming is a good method solved this problem. The mechanical model of the semi-solid materials was treated as that of the continuous porous materials in the high solid volume fraction. The upper bound theory applied for semi-solid metal plastic forming process was developed. The velocity discontinuities exist not only in the tangential component but also in normal component for the kinematically admissible displacement increment filed. The latter one was responsible for a change in solid volume fraction when the material passes the discontinuity. An upper bound analytical model and theoretical method of plastic forming process for semi-solid material has been proposed. The calculating formulas of deformed power were derived. It is theoretical basement to apply further for the practice technology analysis such as the plastic forming of magnesium alloy.

Numerical Simulation on Thixoforming of Wrought Magnesium Alloy

2006 ◽  
Vol 532-533 ◽  
pp. 701-704 ◽  
Author(s):  
Hong Yan ◽  
Chen Xu ◽  
Guo Xiang Chen
Keyword(s):  
Numerical Simulation ◽  
Magnesium Alloy ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Metal Flow ◽  
Rigid Plastic ◽  
Az61 Alloy ◽  
Filling Ability ◽  
Wrought Magnesium Alloy ◽  
Semi Solid

The thixoforming of wrought magnesium alloy was analyzed with computer numerical simulation based on rigid plastic/rigid viscoplastic finite element method. The simulated parameters were chosen and depended on the constitutive model of semi-solid AZ61 alloy that was established using the multiple nonlinear regression method in our prior literature. Thixo mechanical properties of semi-solid AZ61 alloy in high solid volume fraction were also analyzed. Behaviors of metal flow and temperature field were obtained, which were also compared with experimental data in literature. Research showed that the hard deformation magnesium alloy had great filling ability in semi-solid state, and the stress and strain distributions in workpiece after thixoforming were uniform. The semi-solid thixoforming technology has taken priority of the traditional processing.

Preparation of Semi-Solid 357.0 Slurries with Different α-Al Phase Features by Solidification from Full Liquid State and Remelting

2022 ◽  
Vol 327 ◽  
pp. 223-230
Author(s):  
Juan Chen ◽  
Xiao Gang Hu ◽  
Wen Ying Qu ◽  
Min Luo ◽  
Zhong Li ◽  
...  
Keyword(s):  
Particle Size ◽  
Power Law ◽  
Solid Fraction ◽  
Liquid State ◽  
Shape Factor ◽  
Volume Fraction ◽  
Viscosity Model ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Semi Solid

The characteristics of the solid phase, namely the volume fraction, particle size, and morphology, are dominant variables that can determine the viscosity of the semi-solid slurry. However, particle size and morphology were always being ignored and the solid fraction was simply determined using the temperature in the conventional power-law viscosity, resulting in a disagreement in the viscosity values in different researches. To make the power-law viscosity model more accurate for predicting the filling process of semi-solid die casting, it is essential to modify this viscosity model based on particle characteristics. Therefore, there is a fundamental demand to prepare semi-solid slurries with different α-Al phase features at first. This is achieved in this study by two kinds of heat history controlling methods: remelting and solidification, which can get slurries with spherical structure and dendric structure, respectively. The semi-solid 357.0 slurries with 0.11-0.43 solid fraction, 137-182μm particle size, and 0.81-0.90 shape factor were prepared in the remelting process, while dendritic structures (shape factor<0.5) with 0.1 and 0.3 solid fractions were obtained by solidification controlling from the full liquid state. Besides, the effect of parameters on the evolution of the α-Al phase has been discussed. These slurries with different solid features will be further used to quantify the influence of primary phase characteristics on rheological behavior and make the power-law viscosity model more accurate for simulation.

Tribological behavior of AZ91D magnesium alloy composite: effect of hybrid WC – SiO2 nanoparticles

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammed Fahad ◽  
Bavanish B.
Keyword(s):  
Magnesium Alloy ◽  
Wear Rate ◽  
Az91d Alloy ◽  
Hybrid Particles ◽  
Wear Properties ◽  
Sliding Speed ◽  
Composite Effect ◽  
Content Type ◽  
Climate Conditions ◽  
Az91d Magnesium Alloy

Purpose Aviation field requires a material with greater tribological characteristics to withstand the critical climate conditions. Hence, it is of paramount importance to enhance the wear resistance of material. AZ91D magnesium alloy is a light weight material used in the aviation field for the construction work. The purpose of this study is to augment the wear properties of AZ91D alloy by reinforcing with hard particles such as tungsten carbide (WC) and silicon dioxide (SiO2). Design/methodology/approach In this work, three types of composites were fabricated, namely, AZ91D – WC, AZ91D – SiO2 and AZ91D – (WC + SiO2) by ball milling method, and the tribological properties were analyzed using pin-on-disc apparatus. Findings Results showed that the hardness of AZ91D alloy was greatly improved due to the reinforcing effects of WC and SiO2 particles. Wear study showed that wear rate of AZ91D alloy and its composites increased with the increase of applied load due to ploughing effect and decreased with the increase of sliding speed owing to the formation of lubricating tribolayer. Further, the AZ91D – (WC + SiO2) composite exhibited the lower wear rate of 0.0017 mm3/m and minimum coefficient of friction of 0.33 at a load of 10 N and a sliding speed of 150 mm/s due to the inclusion of hybrid WC and SiO2 particles. Hence, the proposed AZ91D – (WC + SiO2) composite could be a suitable candidate to be used in the aviation applications. Originality/value This work is original which deals with the effect of hybrid particles, i.e. WC and SiO2 on the wear performance of the AZ91D magnesium alloy composites. The literature review showed that none of the studies focused on the reinforcement of AZ91D alloy by the combination of carbide and metal oxide particles as used in this investigation.

Microstructure Evaluate System of Semi-Solid Forming

2007 ◽  
Vol 546-549 ◽  
pp. 93-96 ◽  
Author(s):  
Xiao Peng Cui ◽  
Yong Bing Liu ◽  
Zhan Yi Cao ◽  
You Fa Zhang ◽  
Qian Qian Zhang
Keyword(s):  
Magnesium Alloy ◽  
The Other ◽  
Microstructure Analysis ◽  
Analysis Software ◽  
Az91d Magnesium Alloy ◽  
Alloy Microstructure ◽  
Semi Solid

The evaluating rules for semi-solid microstructure were brought up, and the analysis software was developed on MATLAB 7.0 platform in this study. Furthermore, this system can be used not only in the Thixomolding AZ91D magnesium alloy microstructure analysis, but also in the other semi-solid processing microstructure.

Study on Semi-Solid Continuous Roll-Casting Strips of AZ91D Magnesium Alloy

2008 ◽  
pp. 469-473
Author(s):  
Shui Sheng Xie ◽  
You Feng He ◽  
Guo Jie Huang ◽  
Mao Peng Geng ◽  
Ying Zhang
Keyword(s):  
Magnesium Alloy ◽  
Az91d Magnesium Alloy ◽  
Roll Casting ◽  
Semi Solid
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