Entire Symmetric Structure Inchworm-Type Piezoelectric Linear Actuator

2011 ◽  
Vol 480-481 ◽  
pp. 1061-1064 ◽  
Author(s):  
Hong Zhuang Zhang ◽  
Jiang Tian Shi ◽  
De Xin Sun
Keyword(s):  
Melting Point ◽  
Magnesium Alloy ◽  
Tensile Stress ◽  
Liquid Film ◽  
Solidification Process ◽  
Solidification Cracking ◽  
Necessary Condition ◽  
Welding Joint ◽  
Solidification Cracks ◽  
Melting Point Eutectic

The feature of the hot cracks of the welding joint of the MIG welded magnesium alloy AZ91D was studied systematically. The result indicates that the weld of the magnesium alloy displays a high cracking susceptibility. The cracks are mainly formed on the centerline of the weld and in the arc crater at the end of the weld. These cracks propagate along the α-Mg grain boundary, and they belong to the solidification cracking. These solidification cracks are resulted by the joint function of the low melting point liquid film in the weld and the tensile stress suffered by the weld metal during the solidification process. The low melting point liquid film is the internal cause to form the solidification cracks, while the tensile stress is a necessary condition. Limiting the amount of the low melting point eutectic and decreasing the tensile stress of the welding joint are two effective methods to improve the solidification cracking susceptibility of the Mg alloy weld.

Hot Cracking and Microstructure of Welding Joint of Magnesium Alloy AZ91D

2013 ◽  
Vol 753-755 ◽  
pp. 435-438 ◽  
Author(s):  
De Xin Sun ◽  
De Li Cui ◽  
Jiang Tian Shi
Keyword(s):  
Melting Point ◽  
Magnesium Alloy ◽  
Tensile Stress ◽  
Liquid Film ◽  
Solidification Process ◽  
Solidification Cracking ◽  
Necessary Condition ◽  
Welding Joint ◽  
Alloy Az91d ◽  
Solidification Cracks

The microstructure and cracking characteristics of MIG welded magnesium alloy (AZ91D) joint, and the effect of welding speed on cracking susceptibility have been investigated. The result indicates the welded joint consists of primary α-Mg and divorced phases (eutectic α-Mg + eutectic β-Mg17Al12), the latter mainly distributing along the α-Mg grain boundaries. The weld of the magnesium alloy displays a high cracking susceptibility. The cracks are mainly formed in the arc crater at the end of the weld. These cracks propagate along the α-Mg grain boundary, and they belong to the solidification cracking. These solidification cracks are resulted by the joint function of the low melting point liquid film in the weld and the tensile stress suffered by the weld metal during the solidification process. The low melting point liquid film is the internal cause to form the solidification cracks, while the tensile stress is a necessary condition. Limiting the amount of the low melting point eutectic and decreasing the tensile stress of the welding joint are two effective methods to improve the solidification cracking susceptibility of the magnesium alloy weld.

In Situ Observation Method for Quantitative Evaluation of Solidification Phenomena and Solidification Cracks during Welding

2014 ◽  
Vol 782 ◽  
pp. 3-7
Author(s):  
Kenji Shinozaki ◽  
Motomichi Yamamoto ◽  
Kohta Kadoi ◽  
Peng Wen
Keyword(s):  
High Speed ◽  
Video Camera ◽  
Solidification Cracking ◽  
In Situ Observation ◽  
High Speed Video Camera ◽  
Varestraint Test ◽  
Solidification Cracks ◽  
Observation Method ◽  
Solidification Crack

Solidification cracking during welding is very serious problem for practical use. Therefore, there are so many reports concerning solidification cracking. Normally, solidification cracking susceptibility of material is quantitatively evaluated using Trans-Varestraint test. On the other hand, local solidification cracking strain was tried to measure precisely using in-situ observation method, called MISO method about 30 years ago. Recently, digital high-speed video camera develops very fast and its image quality is very high. Therefore, we have started to observe solidification crack using in site observation method. In this paper, the local critical strain of a solidification crack was measured and the high temperature ductility curves of weld metals having different dilution ratios and different grain sizes to evaluate quantitatively the effects of dilution ratio and grain size on solidification cracking susceptibility by using an improved in situ observation method.

scholarly journals A New Method for Phosphorus Recovery Using Magnesium Alloy Electrode under Tensile Stress

2017 ◽  
Vol 30 (1) ◽  
pp. 123-125
Author(s):  
D.Y. Ju ◽  
G. Shi ◽  
O. Hamamoto ◽  
K. Takahashi
Keyword(s):  
Magnesium Alloy ◽  
Tensile Stress ◽  
Phosphorus Recovery ◽  
New Method ◽  
Alloy Electrode

Characterization of AM60 Magnesium Alloy Prepared by Rapid Solidification and Plastic Consolidation Technique

2010 ◽  
Vol 667-669 ◽  
pp. 997-1002
Author(s):  
Tomasz Tokarski
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Bulk Material ◽  
Structure Refinement ◽  
Hot Extrusion ◽  
Solidification Process ◽  
Protective Atmosphere ◽  
Material Structure

Magnesium and its alloys are attractive candidates for automotive and aerospace applications due to their relatively high strength and low density. However, their low ductility determined by hcp structure of material results in limitation of plastic deformation processing. In order to improve ductility as well as mechanical properties, structure refinement processes can be used. It is well known that effective refining of the material structure can be achieved by increasing the cooling rate during casting procedures, hence rapid solidification process (RSP) has been experimented for the fabrication of magnesium alloys. The present paper reports an experimental investigation on the influence of rapid solidification on the mechanical properties of AM60 magnesium alloy. In order to obtain RS material melt spinning process was applied in protective atmosphere, resulting in formation of RS ribbons. Following consolidation of the RS material is necessary to obtain bulk material with high mechanical properties, as so hot extrusion process was applied. It was noticed that application of plastic consolidation by hot extrusion is the most effective process to achieve full densification of material. For comparison purposes, the conventionally cast and hot extruded AM60 alloy was studied as well. The purpose of the present study was to investigate in detail the effect of rapid solidification and extrusion temperature on the structure and mechanical properties of the materials.

Microstructure and mechanical properties of cold metal transfer welded galvanized steel/magnesium alloy dissimilar joints

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040060
Author(s):  
Chao Zhang ◽  
Mingfang Wu ◽  
Yuxin Wang ◽  
Juan Pu
Keyword(s):  
Magnesium Alloy ◽  
Heat Input ◽  
Interface Layer ◽  
Metal Transfer ◽  
Galvanized Steel ◽  
Cold Metal Transfer ◽  
Welding Joint ◽  
Welding Heat Input ◽  
Weld Appearance ◽  
Cold Metal

The joining of magnesium alloy to galvanized steel was realized by cold metal transfer method with AZ31 magnesium alloy welding wire. Weld appearance, microstructure and tensile properties of Mg–steel joints under various welding parameters were investigated with different welding heat inputs. The results showed that magnesium alloy-steel brazed joints had good weld appearance. When the welding heat input was 141 J/mm, Zn elements were enriched in the Zn-rich zone (ZRZ), and the interface layer was composed of a large portion of Mg–Zn phases and minor Mg–Al phases. With the increase of welding heat input, Zn elements in the ZRZ gradually decreased, Fe/Al phase appeared in the interface layer, and the strength of welding joint increased. When the welding heat input was 159 J/mm, the tensile strength of welding joint reached the maximum value of 198 MPa. However, when the welding input was increased to 181 J/mm, Zn element in the ZRZ was burnt and volatilized seriously, resulting in poor wetting and spreading properties of liquid phase at the interface zone of the steel.

Optimization of Process Parameters for Unidirectional Solidification of Magnesium Alloy

2013 ◽  
Vol 750 ◽  
pp. 228-231
Author(s):  
Ming Chen ◽  
Xiao Dong Hu ◽  
Hong Yang Zhao ◽  
Dong Ying Ju
Keyword(s):  
Magnesium Alloy ◽  
Temperature Gradient ◽  
Process Parameters ◽  
Solidification Process ◽  
Optical Microscope ◽  
Field Method ◽  
Unidirectional Solidification ◽  
Grain Structure ◽  
Phase Field Method ◽  
Gradient Distribution

The unidirectional solidification process of magnesium alloy needs to establish a specific temperature gradient in casting mold, the direction of crystal growth and heat flow are in the opposite direction in the unidirectional solidification. The process can better control the grain orientation, and eliminate the horizontal grain boundary, so to attain columnar grain structure and excellent performance of magnesium alloy. In this paper, Numerical simulation is carried out by orthogonal experiments in order to obtain the optimal process parameters according to the actual experimental device. Different process parameters are taken into account, including pulling speed, cooling time and cooling intensity. FEM (finite element method) is employed to calculate the temperature field and reached a straight shape of temperature gradient distribution which is conductive to achieve unidirectional solidification microstructure. PFM(phase field method) is adopted into the microstructure calculation. The microstructure obtained by PFM is in agreement with the actual pattern by the optical microscope observation.

Investigation on Melting Phenomena Generated during Dynamic Formation of Al-Based Coating on Magnesium Alloy

2014 ◽  
Vol 488-489 ◽  
pp. 189-192
Author(s):  
Xiao Ming Wang ◽  
Sheng Zhu ◽  
Xue Qiang Feng ◽  
Yu Xiang Liu
Keyword(s):  
Melting Point ◽  
Magnesium Alloy ◽  
Initial Temperature ◽  
Phase Region ◽  
Nanocrystalline Phase ◽  
Interface Morphology ◽  
Deposition Behavior ◽  
Micro Scale ◽  
Numerical Stimulation ◽  
Dynamic Formation

The deposition behavior of Al-Si particle on magnesium alloy by supersonic particles deposition was investigated by numerical stimulation. The results demonstrated that critical velocity of sprayed particle reduced as its initial temperature increased; Temperature at interface increased rapidly and reached to the value higher than melting point of Al-Si particle and ZM5 magnesium substrate, which predicts the melting possibility for collision interface. Morphology and microstructure of Al-Si coating on magnesium alloy were analyzed by SEM and TEM. The results indicated that there existed large amount of nano/micro-scale grains produced by sputtering and impacting of the melting Al-Si jet. And obvious interface belt had been formed at brim of the deposited particles, nanocrystalline phase region generated by rapid solidification of melting Al-Si particles, justified the occurrence of interface melting phenomena.

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