Effect of Strain Rate on Mechanical Behavior of Extruded AZ31B Magnesium Alloy under Tensile Deformation

2012 ◽  
Vol 560-561 ◽  
pp. 979-983
Author(s):  
Chang Jian Geng ◽  
Bao Lin Wu ◽  
Yan Dong Wang

Uni-axial tensile test was conducted at room temperature on a weak texture AZ31B magnesium alloy at different strain rate, from 2.8×10-5s-1 to 1.1×10-1s-1. The mechanical behavior was investigated. It was found that as strain rate is increased, flat character of the stress-strain curves can be found and {10-12} tension twinning is responsible for this phenomenon. The sample exhibites a brittle fracture at 1.1×10-1s-1 strain rate while exhibites a ductile fracture character at 2.8×10-5s-1 strain rate.

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744014
Author(s):  
M. Li ◽  
Q. W. Jiang

Tensile deformation behavior of ultrafine-grained (UFG) copper processed by accumulative roll-bonding (ARB) was studied under different strain rates at room temperature. It was found that the UFG copper under the strain rate of 10[Formula: see text] s[Formula: see text] led to a higher strength (higher flow stress level), flow stability (higher stress hardening rate) and fracture elongation. In the fracture surface of the sample appeared a large number of cleavage steps under the strain rate of 10[Formula: see text] s[Formula: see text], indicating a typical brittle fracture mode. When the strain rate is 10[Formula: see text] or 10[Formula: see text] s[Formula: see text], a great amount of dimples with few cleavage steps were observed, showing a transition from brittle to plastic deformation with increasing strain rate.


2004 ◽  
Vol 449-452 ◽  
pp. 305-308
Author(s):  
Lei Wang ◽  
Toshiro Kobayashi ◽  
Chun Ming Liu

Tensile test at loading velocities up to 10 m·s-1(strain rate up to 3.2x102s-1) was carried out forr SiCp/AC4CH composite and AC4CH alloy. The microstructure of the composite before and after tensile deformation was carefully examined with both optical microscope and SEM. The experimental results demonstrated that the ultimate tensile strength (UTS) and yield strength (YS) increase with increasing loading velocity up to 10 m·s-1. Comparing with AC4CH alloy, the fracture elongation of the composite is sensitivity with the increasing strain rate. The YS of both the composite and AC4CH alloy shows more sensitive than that of the UTS with the increasing strain rate, especially in the range of strain rate higher than 102s-1.


Author(s):  
Ju Guo ◽  
Xiao-Lei Cui ◽  
Wen-Kai Zhao ◽  
Cheng-Zhong Chi ◽  
Xiao-Qing Cao ◽  
...  

In this paper, to investigate the effect of loading method of pulse current on the tensile deformation behavior of AZ31B magnesium alloy sheet, the intermittent pulse current with short-time and high-frequency was introduced in uniaxial tensile tests and the influence of duty ratio and loading time of pulse current on the deformation behavior of AZ31B magnesium alloy sheet was discussed. The strain and temperature field distributions on the specimens were measured during the intermittent pulse electrically-assisted tension (IPEAT), and the microstructure and fracture morphology under different pulse current conditions were observed. Results shows appropriate pulse current parameters can effectively improve the elongation of AZ31B magnesium alloy sheet. The strain of the sample is closely related to temperature distribution. With the deformation of the sample, the temperature on the sample increases gradually and the temperature distribution is non-uniform along the tensile direction, resulting in an inhomogeneous strain distribution of the sample. In addition, grain growth and dynamic recrystallization were observed on the AZ31B magnesium alloy sheet in different degrees under intermittent pulse current. Fracture morphology analysis shows that the number of dimples and tearing edges increased on the fracture obtained under IPEAT. The microhardness analysis shows that when intermittent pulse current is applied in the tensile test, the hardness of the sheet may change. This research provides an effective idea for the forming process of magnesium alloy sheets, which can be used to form large size thin-walled sheet components, and can significantly improve the forming quality of the sheets.


2011 ◽  
Vol 128-129 ◽  
pp. 397-402
Author(s):  
Lian Fa Yang ◽  
Liang Yi ◽  
Chen Guo

The formability of the magnesium alloy sheets is poor at room temperature even though the magnesium alloy sheets are attractive because of their excellent characteristics. Application of pulsating hydroforming is a new and effective method to improve the formability. The effects of the pressure amplitude on the maximum bulging height and minimum wall thickness of the formed parts of AZ31B magnesium alloy sheets are examined using finite element simulations. It is shown that the distribution of maximum bugling height and minimum wall thickness is similar for different pressure amplitude A, and a uniform expansion in bulging region is obtained, the cause of the uniform expansion obtained may be caused by the variation of stress components. The AZ31B sheet has an excellent performance in formability when the pressure amplitude and pulsating frequency are properly selected.


Author(s):  
J. A. Ávila ◽  
H. E. Jaramillo ◽  
F. Franco

The mechanical behavior of butt welds made on AZ31B magnesium alloy plates by solid-state friction stir welding (FSW) and gas tungsten arc welding (GTAW) is presented. Fatigue, tensile strength, and hardness tests were performed. Also, fractographic analyses of the weld microstructures were conducted. Tests results show that the fatigue performance of FSW joints was superior to that of conventional welding (GTAW).


2009 ◽  
Vol 618-619 ◽  
pp. 101-104
Author(s):  
Li Wang ◽  
Qiang Luo ◽  
Yan Zhang Liu ◽  
Yong Chen ◽  
Dan Qi Sun

Abstract The effects of hydrogen on the hydrogen embrittlement of Ti-2Al-2.5Zr alloy was investigated by tensile test, slow strain rate test (SSRT), and the amount of absorbed hydrogen of Ti-2Al-2.5Zr alloy was studied by immersion test in alkaline steam water at a pressure of 8.5MPa. The results indicated that the hydrides(TiH2) in Ti-2Al-2.5Zr alloy formed as platelets and were identified as face-centered cubic δ-hydride. At room temperature, hydrogen and formed hydrides induced increase of the intensity and caused loss in the ductility. In alkaline steam water at a pressure of 8.5MPa, the hydrogen embrittlement susceptibility index (IHE) of Ti-2Al-2.5Zr alloy increased with increasing hydrogen content, and the IHE value of the alloy with 350ppm H was less than 0.1. Moreover the amount of absorbed hydrogen of Ti-2Al-2.5Zr alloy increased with increasing of immersion time, and absorbed hydrogen was still less than 50ppmH even when immersion time reached 13000h.


2004 ◽  
pp. 13-31

Abstract This chapter focuses on mechanical behavior under conditions of uniaxial tension during tensile testing. It begins with a discussion on the parameters that are used to describe the engineering stress-strain curve of a metal, namely, tensile strength, yield strength or yield point, percent elongation, and reduction in area. This is followed by a section describing the parameters determined from the true stress-true strain curve. The chapter then presents the mathematical expressions for the flow curve. Next, it reviews the effect of strain rate and temperature on the stress-strain curve. The chapter then describes the instability in tensile deformation and stress distribution at the neck in the tensile specimen. It discusses the processes involved in ductility measurement and notch tensile test in tensile specimens. The parameter that is commonly used to characterize the anisotropy of sheet metal is covered. Finally, the chapter covers the characterization of fractures in tensile test specimens.


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