Effects of the rolling strain rate-induced microstructure on bio-corrosion behavior of the Mg–5Zn–1Mn alloy sheet

2019 ◽  
Vol 6 (8) ◽  
pp. 0865c5 ◽  
Author(s):  
Hui Guo ◽  
Jihua Chen ◽  
Hongge Yan ◽  
Weijun Xia ◽  
Bin Su ◽  
...  
Keyword(s):  
Strain Rate ◽  
Corrosion Behavior ◽  
Alloy Sheet ◽  
Rolling Strain

The Superplastic Properties and Microstructures Evolution of High Nb Ti3Al Based Alloy

2016 ◽  
Vol 838-839 ◽  
pp. 568-573 ◽  
Author(s):  
Xiu Quan Han ◽  
Ming Jie Fu
Keyword(s):  
Strain Rate ◽  
Work Hardening ◽  
Deformation Temperature ◽  
Volume Fraction ◽  
Alloy Sheet ◽  
Deformation Condition ◽  
Maximum Elongation ◽  
Β Phase ◽  
Superplastic Properties ◽  
Softening Stage

The superplasticity of high Nb Ti3Al based alloy - Ti-23Al-17Nb (at.%) alloy sheet under the conditions of 940~1000°C and 5.5×10-5s-1~1.7×10-3s-1are studied. The results show the elongation changes as a parabola with the deformation temperature increasing, and the maximum elongation obtained at 960°C and 5.5x10-5s-1 is 1447.5%. Work hardening stage increases much more than softening stage when strain rate is decreased due to the increasing of element Nb. Compared with primary microstructure, the lath-like α2 grains gradually disappeared, the α2 grains became more equiaxed, and the content and size of α2 grains are decreasing with increasing of deformation temperature. The volume fraction ratio of α2 and β phase at the optimum deformation condition is 50:50%. The cavities mechanism at the fracture tip was discussed; it can be defined that the cavities could be avoided when deformation temperature is higher than 940°C.

Tensile Deformation Behavior of 5A90 Al-Li Alloy Sheet at Elevated Temperature

2011 ◽  
Vol 66-68 ◽  
pp. 70-75 ◽  
Author(s):  
Gao Shan Ma ◽  
Song Yang Zhang ◽  
Han Ying Wang ◽  
Min Wan
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Tensile Deformation ◽  
Alloy Sheet ◽  
Hot Forming ◽  
Uniaxial Tensile ◽  
Sensitivity Index ◽  
Tensile Deformation Behavior ◽  
Increasing Temperature

Uniaxial tensile deformation behavior of 5A90 aluminium-lithium alloy sheet is investigated in the hot forming with the temperature range of 200-450°C and strain rate range of 0.3×10-3-0.2×10-1s-1. It is found that the flow stress of 5A90 Al-Li alloy in uniaxial tension increase with increasing strain rate and decrease with increasing temperature, however, the tendency of total elongation is just the reverse, and the optimum forming temperature is 400°C. The strain rate sensitivity index (m-value) remarkably increases with increasing temperature for a given strain rate. It is shown that 5A90 Al-Li alloy sheet displays the sensitivity to the strain rate at elevated temperatures. For a given strain rate, the strain hardening index (n-value) decreases with increasing temperature, whereas the n-value increases above 350°C. The constitutive equation of stress, strain and strain rate for 5A90 Al-Li alloy at any temperature is obtained by fitting the experimental data, which gave a good flow stress model for the FEM simulation of hot forming.

Research on Flow Stress of Magnesium Alloy Sheet under Warm and High Strain Rate Forming Condition

2011 ◽  
Vol 189-193 ◽  
pp. 2522-2525
Author(s):  
Zheng Hua Meng ◽  
Shang Yu Huang ◽  
Jian Hua Hu
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Process Simulation ◽  
High Strain ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Rate Condition ◽  
Magnesium Alloy Sheet

Process simulation is a powerful tool to predict material behaviors under specified deformation conditions, so as to optimize the processing parameters. The equation for flow stress is important to numerically analyze. However, the reported constitutive equations of magnesium alloy are only suitable for processing simulation with strain rate between 0.001-1s-1. In this paper, the strain-stress behavior of AZ31 under warm and high strain rate (>103s-1) condition has been investigated by split Hopkinson pressure bar experiments at elevated temperature. The results show that the influence of the temperature on flow stress is more obvious than that of strain rate; the flow stress decreases with the rise of temperature at a certain strain rate. Based on Johnson-Cook model, the constitutive equation of AZ31 magnesium alloy under warm and high strain rate condition has been given out by fitting the experimental data, which can be applied in process simulation of AZ31 magnesium alloy sheet forming.

High Strain Rate Superplasticity and Microstructure Evolution in a Coarse-Grained Mg-Gd-Y-Zr Rolled Sheet

2014 ◽  
Vol 900 ◽  
pp. 719-724
Author(s):  
Ying Zheng ◽  
Chang Ping Tang ◽  
Yun Lai Deng
Keyword(s):  
Electron Microscopy ◽  
Dynamic Recrystallization ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Microstructural Analysis ◽  
Alloy Sheet ◽  
Coarse Grained ◽  
Dislocation Slip ◽  
Rolled Sheet

Superplasticity at high deformation rates is desirable in order to make superplastic forming more practical. High strain rate superplastic behavior and microstructure of the rolled Mg-Gd-Y-Zr alloy sheet were investigated. For the purposes, tensile tests at the strain rate of 0.01 s-1were conducted, which revealed that the sheet exhibited elongations of 180%~266%. Post-deforming microstructures were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy, while crystallographic orientation information was obtained from macro-texture analysis. The results show that the high strain rate superplasticity was attributed to class-I creep accommodated by dynamic recrystallization. It is suggested from microstructural analysis results that the interaction between second phases and dislocation facilitated dynamic recrystallization. The macro-texture at the strain of 0.8 still exhibited some characteristics of the crystal rotation arising from dislocation slip despite the occurrence of DRX.

Effect of Heat Treatments on Stress Corrosion Behavior of 7050 Al Alloys in 3.5% NaCl Solution

2016 ◽  
Vol 877 ◽  
pp. 543-549
Author(s):  
Wei Wei Ren ◽  
Xing Feng Zhan ◽  
Lin Chi Zou ◽  
Qiang Li ◽  
Jun Feng Chen
Keyword(s):  
Corrosion Resistance ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Heat Treatments ◽  
Al Alloys ◽  
Slow Strain Rate ◽  
Nacl Solution ◽  
Stress Corrosion Resistance

Effect of heat treatments on the stress corrosion behavior of 7050 Al alloys in 3.5% NaCl solution has been investigated using slow strain rate tensile (SSRT) test. During the slow strain rate tensile process, electrochemical impedance spectroscopy (EIS) in real time was carried out to characterize the electrochemical behavior for different tempers 7050 Al alloys. The investigation shows that both the stress corrosion resistance of 7050 Al alloys is controlled by heat treatments due to the different precipitates state. The improvement of stress corrosion resistance is contributed to the tiny precipitates in matrix which are beneficial to corrosion potential and maintain passivation, and precipitates discontinuous distribution at grain boundary which obstruct intergranular crack connection. Moreover, base on the results, we find out retrogression and re-aging (RRA, i.e., T6 + 200 °C/ retrogression + water quench + T6) increases both tensile strength and stress corrosion resistance. The optimized of retrogression time is 30 minutes.

Tensile Behaviour of 6082 Aluminium Alloy Sheet under Different Conditions of Heat Treatment, Temperature and Strain Rate

2009 ◽  
Vol 423 ◽  
pp. 105-112 ◽  
Author(s):  
I. Torca ◽  
A. Aginagalde ◽  
J.A. Esnaola ◽  
L. Galdos ◽  
Zigor Azpilgain ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Room Temperature ◽  
Microstructural Analysis ◽  
Weight Ratio ◽  
Alloy Sheet ◽  
Treatment Temperature ◽  
Tensile Behaviour

Aluminium alloys are more and more important for the automotive industry due to their high strength to weight ratio and their elevated ductility; they are used for many different parts in automobiles as exterior panels, structural parts, brake housings and others. However, their formability at room temperature is limited. This inconvenient can be improved by increasing the forming temperature of the part. That lack of formability has lead to this research project dealing with the tensile behaviour of aluminium alloys sheets, at different conditions of temperature and strain rate. The analyzed material has been 6082 aluminium alloy, under two different heat treatment conditions (O and T6). Material testing has been carried out in a temperature range between room temperature and 250°C, and a strain rate range between 0.001s-1 and 0.1s-1. Testing samples have been obtained from laminated sheet of 1.5mm thickness. This article shows that the alloy under T6 condition has a reduced formability, even in warm conditions. In order to get higher deformation values an annealed condition is proposed to form the material. The effect of T6 heat treatment and O annealing treatment in the uniaxial warm formability is discussed and a microstructural analysis is also presented in order to understand the differences on the alloy behaviour.

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