The Effect of Crystal Orientation on Damping Capacity in Rolled AZ31 Magnesium Alloy

2018 ◽  
Vol 941 ◽  
pp. 1127-1131 ◽  
Author(s):  
Ju Ho Kwak ◽  
Min Seong Ko ◽  
Kwon Hoo Kim

The effect of crystal orientation on damping capacity is studied on hot rolled AZ31 magnesium alloy. AZ31 magnesium alloys which was machined out parallel to rolled direction and perpendicular to rolled direction were investigated about the relationship between the initial texture and damping capacity. The specimens are annealed at 623 K and time ranging from 30 to 180 minutes. After heat treatment recrystallization is occurred. Then, average grain size and damping capacity are increased with increasing annealing time. Two types of specimens show different main component of texture and damping capacity respectively. It is found that initial texture was affected on damping capacity.

2017 ◽  
Vol 23 (3) ◽  
pp. 222 ◽  
Author(s):  
Ondřej Hilšer ◽  
Stanislav Rusz ◽  
Wojciech Maziarz ◽  
Jan Dutkiewicz ◽  
Tomasz Tański ◽  
...  

<p>Equal channel angular pressing (ECAP) method was used for achieving very fine-grained structure and increased mechanical properties of AZ31 magnesium alloy. The experiments were focused on the, in the initial state, hot extruded alloy. ECAP process was realized at the temperature 250°C and following route Bc. It was found that combination of hot extrusion and ECAP leads to producing of material with significantly fine-grained structure and improves mechanical properties. Alloy structure after the fourth pass of ECAP tool with helix matrix 30° shows a fine-grained structure with average grain size of 2 µm to 3 µm and high disorientation between the grains. More experimental results are discussed in this article.</p>


2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Ming Chen ◽  
Xiaodong Hu ◽  
Hongyang Zhao ◽  
Dongying Ju

A large reduction rolling process was used to obtain complete dynamic recrystallization (DRX) microstructures with fine recrystallization grains. Based on the hyperbolic sinusoidal equation that included an Arrhenius term, a constitutive model of flow stress was established for the unidirectional solidification sheet of AZ31 magnesium alloy. Furthermore, discretized by the cellular automata (CA) method, a real-time nucleation equation coupled flow stress was developed for the numerical simulation of the microstructural evolution during DRX. The stress and strain results of finite element analysis were inducted to CA simulation to bridge the macroscopic rolling process analysis with the microscopic DRX activities. Considering that the nucleation of recrystallization may occur at the grain and R-grain boundary, the DRX processes under different deformation conditions were simulated. The evolution of microstructure, percentages of DRX, and sizes of recrystallization grains were discussed in detail. Results of DRX simulation were compared with those from electron backscatter diffraction analysis, and the simulated microstructure was in good agreement with the actual pattern obtained using experiment analysis. The simulation technique provides a flexible way for predicting the morphological variations of DRX microstructure accompanied with plastic deformation on a hot-rolled sheet.


2007 ◽  
pp. 255-258
Author(s):  
Xin Sheng Huang ◽  
Kazutaka Suzuki ◽  
Akira Watazu ◽  
Ichinori Shigematsu ◽  
Naobumi Saito

2010 ◽  
Vol 654-656 ◽  
pp. 711-714 ◽  
Author(s):  
Susumu Mizunuma ◽  
Takamichi Iizuka ◽  
Kazuhiro Mitsui ◽  
Hidehito Okumura ◽  
Masahide Kohzu

Grain refinement and crystal orientation of magnesium alloy AZ31 under torsion extrusion with a square-hole die are investigated. The optimum temperature and ratio of the die rotation speed to the extrusion speed were clarified, resulting in uniformly distributed fine grains with sizes in the range 1- m over the entire cross section of the worked specimen. The crystal orientation of the specimen was determined by electron backscatter diffraction and compared with that of a conventionally extruded specimen. In the case of torsion extrusion, a very strong <0001> texture was observed along the extrusion axis, especially in the center region of the cross section. In contrast, the <0001> direction of many grains in the conventionally extruded specimen tended to be perpendicular to the extrusion axis.


2015 ◽  
Vol 661 ◽  
pp. 105-112
Author(s):  
Yeong Maw Hwang ◽  
Tso Lun Yeh

Material’s plastic deformation by hot forming processes can be used to make the materials generate dynamic recrystallization (DRX) and fine grains and accordingly products with more excellent mechanical properties, such as higher strength and larger elongation can be obtained. In this study, compression tests and water quenching are conducted to obtain the flow stress of the materials and the grain size after DRX. Through the regression analysis, prediction equations for the magnesium alloy microstructure were established. Simulations with different rolling parameters are conducted to find out the relationship between the DRX fractions or grain sizes of the rolled products and the rolling parameters. The simulation results show that rolling temperature of 400°C and thickness reduction of 50% are the optimal conditions. An average grain size of 0.204μm-0.206μm in the microstructure is obtained and the strength and formability of ZK60 magnesium alloys can be improved.


2016 ◽  
Vol 850 ◽  
pp. 784-789
Author(s):  
Song Lin Chen ◽  
Da Tong Zhang

AZ31 magnesium alloy was friction stir spot welded in air and cooling in water. The effect of the enhanced cooling rate on the microstructure and mechanical properties of the joint was analyzed. The results showed that flowing water had obvious cooling effect instantaneously, which significantly restrained the growth of dynamic recrystallized grains. The average grain size in stir zone was 1.3μm in cooling water condition, which is far smaller than that of the joint prepared in air cooling condition. Under the condition of enhanced cooling, the microhardness in stir zone significantly increased, the ultimate tensile load (~ 3.99kN) increased by 15.7%, and the tensile deformation value (~ 3.65 mm) increased by 62.2%. Dimples in SEM fracture morphologies indicated the better plastic deformation capacity of joints prepared by cooling water, which failed through a mixture mode of ductile and brittle fracture.


2009 ◽  
Vol 475 (1-2) ◽  
pp. 126-130 ◽  
Author(s):  
S.M. Fatemi-Varzaneh ◽  
A. Zarei-Hanzaki ◽  
M. Haghshenas

2013 ◽  
Vol 341-342 ◽  
pp. 296-300
Author(s):  
Xiao Yan Gu ◽  
Huan Li ◽  
Ying Gao

AZ31 magnesium alloy was welded by the YAG laser. The plasma of laser welding was studied by the spectra and the plasma temperature was also calculated. The relationship between the welding parameters and plasma temperature was studied. The paper shows that the cooling effect of the plasma using helium is significant. Laser plasma temperature decreases from the center to the periphery and the temperature in the center is higher than 9000K. The evaporation of Mg element concentrates in the center of the laser plasma.


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