scholarly journals Structures and mechanical properties of an AZ91D magnesium alloy solidified by the semi-solid stir-casting process.

1992 ◽  
Vol 42 (9) ◽  
pp. 504-510 ◽  
Author(s):  
Takahisa HITOMI ◽  
Akira YUASA ◽  
Shigeharu KAMADO ◽  
Yo KOJIMA
2006 ◽  
Vol 324-325 ◽  
pp. 499-502
Author(s):  
Ze Sheng Ji ◽  
Mao Liang Hu ◽  
Xiao Yu Chen

AZ91D magnesium alloy is prepared by hot extrusion of recycled machined chips and its fractures and mechanical properties are investigated at various extrusion conditions. Cold-press is employed to prepare extrusion billets of AZ91D magnesium alloy chips, and then the billets are hot extruded at 573K-723K with an extrusion ratio of 11:1. The results show that tensile strength and elongation of the extrusion magnesium alloy with the extrusion temperature of 673K and the extrusion rate of 0.08mm/s can reach 380MPa and 6%, respectively. Fracture surface presents a mix mechanism of dimple-like fracture and gliding fracture. Due to grain refinement by cold-press and hot extrusion, mechanical properties of extruded rods are much higher than those of as-cast AZ91D magnesium alloy. Also, much lower energy consumption is necessary for this recycling compared to the conventional casting process. Solid state recycling is an efficient method for magnesium alloy chips recycling.


2005 ◽  
Vol 488-489 ◽  
pp. 397-400
Author(s):  
Hwa Chul Jung ◽  
Ye Sik Kim ◽  
Kwang Seon Shin

The demand for magnesium alloys has increased significantly during the past decade in the automotive and electronic industries where weight reduction becomes increasingly an important issue. At present, high-pressure die casting (HPDC) is a dominant process in production of magnesium alloy components. However, magnesium alloy components produced by HPDC suffer from porosity problem and this limits the enhancement of mechanical properties through subsequent heat treatments. The semi-solid processing (SSP) is an emerging new technology for near-net shape production of engineering components, in which the alloys are processed in the temperature range where the liquid and solid phases coexist. The SSP has various advantages over the conventional casting processes. It offers the castings with high integrity and less porosity and allows subsequent heat treatments for enhancement of mechanical properties. For these advantages, the SSP of magnesium alloys has received increasing attention in recent years. In the present study, the continuous casting process was developed for the production of magnesium billets for the subsequent SSP. The process utilizes an electromagnetic stirring system in order to obtain desired microstructure with an excellent degree of homogeneity in both microstructure and composition. Prototypes of an air conditioner cover and a telescope housing were produced using the SSP of the continuously cast magnesium alloy billets.


2006 ◽  
Vol 116-117 ◽  
pp. 267-270 ◽  
Author(s):  
Ju Fu Jiang ◽  
Shou Jing Luo

The thixoforging process in which magazine plates of AZ91D magnesium alloy were thixoforged in semi-solid state using semi-solid billets prepared by common SIMA method and new SIMA method was investigated. The results show that the pressure has a great influence on the semi-solid billet’s ability to fill die’s cavity. When the pressure is 500KN, the semi-solid billet can’t fill the die’s cavity completely. When the pressure is 2000KN, the semi-solid billet can fill the die’s cavity completely. Room temperature mechanical properties, such as yield strength of 201.4MPa, ultimate tensile strength of 321.8MPa and elongation of 15.3%, can be obtained successfully when the technological parameters, including pressure of 200KN, die preheating temperature of 723K, holding for 20min at 818K, are satisfied. Comparing with common SIMA, mechanical properties of room temperature and high temperature at 373Kare enhanced heavily.


2008 ◽  
Vol 141-143 ◽  
pp. 617-622
Author(s):  
Zhi Ming Du ◽  
Shui Sheng Xie ◽  
Ping Wu ◽  
Yan Ying Zhang

High quality magnesium alloy sheets with non-dendritic microstructure can be manufactured by the technique which incorporates semi-solid processing with continuous roll stripcasting. In particular, the process is believed to be cost-effective in mass production of magnesium sheet products. The processing parameters, such as roll speed and temperature, have significant influence on roll strip-casting process. In this paper, the commercial software, DEFORM-3D, for deformation simulation of bulk materials was used to carry out the simulation of roll strip-casting process for AZ91D magnesium alloy in semi-solid state, and the distribution of equivalent stress, equivalent strain and temperature was obtained. Based on the results, the optimization of processing parameters was discussed.


2008 ◽  
Vol 141-143 ◽  
pp. 469-473
Author(s):  
Shui Sheng Xie ◽  
You Feng He ◽  
Guo Jie Huang ◽  
Mao Peng Geng ◽  
Ying Zhang

Semi-solid Continuous roll-casting process applied to produce the AZ91D magnesium strips and its microstructure was studied in this paper. In order to examine further process ability and forming property of the roll-casting strips, hot and cold rolling and punching experiments were investigated. It was clarified that it is significant to combine the semi-solid process techniques with roll-casting techniques, through which we can get high quality magnesium alloy strips with nondendritic structure and improve the overall properties of the products. The largest deformation by cold rolling and hot rolling can reach 18% and 21% respectively with one-pass roller.


2016 ◽  
Vol 850 ◽  
pp. 790-801
Author(s):  
Hong Xu ◽  
Xin Zhang ◽  
Chang Shun Wang ◽  
Jin Chuan Hu ◽  
Cheng Wang ◽  
...  

AZ91D magnesium alloy is one of the most widely used magnesium alloys in the production of metal forming, which use the characteristics from liquid state to solid state of metal to form. The present status of the research and application of the semi-solid forming for AZ91D magnesium alloys at present was reviewed in this paper, including the microstructural characteristics, the thixotropic and rheological behavior, the forming process of semi-solid for AZ91D magnesium alloys and the mechanical properties of the parts made of semi-solid magnesium alloys. The developing prospects and the key points of the semi-solid forming for AZ91D magnesium alloys were forecasted, and the industrial application of the alloy were also discussed.


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