Stress-Strain Behavior of Hot-Compression Mg-Li Alloy

2012 ◽  
Vol 485 ◽  
pp. 283-287
Author(s):  
Jian Bo Wen ◽  
Qian Liu ◽  
Deng Yu Gai
Keyword(s):  
Regression Analysis ◽  
Flow Stress ◽  
Hot Compression ◽  
Compression Process ◽  
Stress Strain ◽  
Arithmetic Average ◽  
Strain Behavior ◽  
Set Up ◽  
Gleeble 3500 ◽  
Gleeble 3500 System

The stress-strain behavior of hot-compression Mg-Li alloy was investigated by using a physical simulator Gleeble-3500 system. And the constitutive equation was set up by regression analysis and BP neural networks. Results show that the dynamic recrystallization occured during the hot-compression process. The grain size of the alloy increased and the stress decreased with increasing temperature. Regression analysis indicates that the flow stress can be expressed by hyperbolic sine model and the arithmetic average of errors is 14.13%. Training the flow stress prediction model with MatLab by an improved BP，the maximum arithmetic average of errors is 4.27%. The predicted stress-strain curves are in good agreement with the experimental results.

Numerical Simulation of Pore Evolution of 7050 Aluminum Alloy during Hot Compression Process

2016 ◽  
Vol 879 ◽  
pp. 2119-2124
Author(s):  
Yong Fu Wu ◽  
Hui Xue Jiang ◽  
Chun Zou ◽  
Kang Cai Yu ◽  
Hiromi Nagaumi
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Flow Stress ◽  
Hot Compression ◽  
Compression Process ◽  
Bulk Metal ◽  
Inner Pressure ◽  
7050 Aluminum Alloy ◽  
Pore Evolution ◽  
Evolution Behavior

Evolution behavior of pores in 7050 aluminum alloy during hot compression process has been investigated by finite element (FE) numerical simulation. The representative volume element (RVE) model containing one isolated pore is built, in which the gas in pore is treated as ideal gas. Effects of initial pore inner pressure and deformation temperature on pore evolution have been investigated. The simulation results indicate that stress concentration exists around the pore in the compressing process. At the simple compression condition, the inner pressure of the pore increases but the volume decreases as the bulk metals deforms. However, the volume reaches a plateau after the yield point of bulk metal. The plateau volume depends on the initial inner pressure of the pore and the flow stress of the bulk metal. Since the inner pressure of the pore balances with the flow stress of bulk metal at the interface, the temperature affects the evolution behavior of the pore through its influence on the flow stress of the bulk metal primarily.

A Study into the Behavior of an Aluminum Foam under Compression

2013 ◽  
Vol 535-536 ◽  
pp. 64-67
Author(s):  
C. Mahesh ◽  
Anindya Deb ◽  
S.V. Kailas ◽  
C. Uma Shankar ◽  
T.R.G. Kutty ◽  
...  
Keyword(s):  
Aluminum Foam ◽  
Absorption Capacity ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Stress Strain ◽  
Compression Loading ◽  
Strain Behavior ◽  
Axial Crush ◽  
Set Up ◽  
Energy Absorbing

The characterization of a closed-cell aluminum foam with the trade name Alporas is carried out here under compression loading for a nominal cross-head speed of 1 mm/min. Foam samples in the form of cubes are tested in a UTM and the average stress-strain behavior is obtained which clearly displays a plateau strength of approximately 2 MPa. It is noted that the specific energy absorption capacity of the foam can be high despite its low strength which makes it attractive as a material for certain energy-absorbing countermeasures. The mechanical behavior of the present Alporas foam is simulated using cellular (i.e. so-called microstructure-based) and solid element-based finite element models. The efficacy of the cellular approach is shown, perhaps for the first time in published literature, in terms of prediction of both stress-strain response and inclined fold formation during axial crush under compression loading. Keeping in mind future applications under impact loads, limited results are presented when foam samples are subjected to low velocity impact in a drop-weight test set-up.

Deformation Behavior and Microstructure Evolution of 6063 Alloy during Hot Compression

2018 ◽  
Vol 913 ◽  
pp. 63-68 ◽  
Author(s):  
Zhu Hua Yu ◽  
Da Tong Zhang ◽  
Wen Zhang ◽  
Cheng Qiu
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Shear Bands ◽  
Hot Compression ◽  
Al Alloy ◽  
Strain Rates ◽  
Compression Tests ◽  
Softening Effect ◽  
6063 Al Alloy ◽  
Gleeble 3500

Hot compression tests of homogenized 6063 Al alloy were carried out in the temperatures range from 390°C to 510°C and strain rates from 1s-1 to 20s-1 on a Gleeble-3500 thermal simulation machine. The results showed that the flow stress decreased with increasing deformation temperature or decreasing strain rate. The dynamic softening effect was more obvious when the alloy was deformed at strain rate of 20 s-1. The Arrhenius-type constitutive equation with strain compensation can accurately describe the flow stress of 6063 aluminum alloy during hot compression. Shear bands appeared in grains interior when the alloy deformed at high strain rates, corresponding to high Zenner-Hollomon (Z) parameters. When deformed under the conditions with low Z parameters, the dynamic recrystallization started occurred.

Flow Stress Behaviour of TWIP Steel during the Hot Compression Deformation

2011 ◽  
Vol 194-196 ◽  
pp. 1235-1241
Author(s):  
Qiang Liu ◽  
De Jun Li ◽  
Feng Shou Shangguan ◽  
Yao Rong Feng ◽  
Ke Tong
Keyword(s):  
Flow Stress ◽  
Hot Deformation ◽  
Twip Steel ◽  
Linear Regression Analysis ◽  
Typical Feature ◽  
True Stress ◽  
Hot Compression ◽  
Stress Strain ◽  
Hot Compression Deformation ◽  
Compression Deformation

The hot deformation behavior of Fe-25Mn-3Si-3Al TWIP steel were investigated by isothermal single-pass compression on Gleeble-3500 thermal simulator at the temperature range of 900°C to 1100°C and the strain rate range of 0.01s-1to 1s-1. The results showed that the true stress-strain curves of Fe-25Mn-3Si-3Al steel had a typical feature which often appears during the hot deformation process of metals and alloys with high stacking fault energies. In true stress-strain curves, No obvious flow stress peak was observed. With the increase of strain, flow stress reaches the saturation value, indicating that the hot deformations of these conditions are dynamic recovery. The hot compression deformation of Fe-25Mn-3Si-3Al steel can be represented by Arrhenius model. The constitutive equation of Fe-25Mn-3Si-3Al steel under hot compression deformation is calculated by a linear regression analysis. The activation energy for hot deformation of the experimental steel is 422.51kJ/mol.

Dynamic Stress-Strain Behavior of AZ91 Alloy at High-Strain Rate

2007 ◽  
Vol 546-549 ◽  
pp. 89-92 ◽  
Author(s):  
Gui Ying Sha ◽  
En Hou Han ◽  
Yong Bo Xu ◽  
Lu Liu
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Dynamic Stress ◽  
Split Hopkinson Pressure Bar ◽  
Az91 Alloy ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Strain Rate Effects ◽  
Strain Behavior ◽  
Pressure Bar

The dynamic stress-strain behavior of the AZ91 alloys in different treatment conditions (as-cast, T4 and T6) was investigated by means of split Hopkinson pressure bar. It was found that the flow stress increased at first, and then declined with the strain rate increasing at the range of 102~103s-1 for the alloys in these three conditions. And the alloys exhibited both positive and negative strain rate effects. The former was caused by strain rate strengthening and the latter was caused by strain rate weakening. However the flow stress for the alloy in aged condition at the same strain rate was higher than both of the alloys in as-cast and solution conditions. The study also showed that the maximum strains of the alloys in different conditions increased with the strain rate increasing, and the strain rate to fracture for the alloy in solution condition was higher than those of other two alloys. The work-hardening of α–Mg matrix and the reinforcement of β-Mg17Al12 phases led to the strengthening of the alloy, while thermal softening of matrix, the fracture of β phases and initiation and propagation of the cracks were responsible for the weakening of the alloy.

The Large Strain Flow Stress Behaviour of Aluminium Alloys as Measured by Channel-Die Compression (20-500°C)

2006 ◽  
Vol 519-521 ◽  
pp. 783-788 ◽  
Author(s):  
A. Bacha ◽  
Claire Maurice ◽  
Helmut Klocker ◽  
Julian H. Driver
Keyword(s):  
Flow Stress ◽  
Sheet Metal ◽  
Large Strain ◽  
Large Strains ◽  
Stress Strain ◽  
Sheet Plane ◽  
Die Set ◽  
Flow Stress Data ◽  
Set Up ◽  
Stress Behaviour

Two recent methods for obtaining flow stress-strain relations up to large strains of order 1.5 by channel-die compression are presented: i) for sheet metal formability tests, composite samples have been made of glued sheet layers and deformed at room temperature in a channel-die with the compression axis directed along one of the sheet metal edge directions, i.e. RD or TD. The sheet plane is parallel to the lateral compression die face. It is shown that, using a suitable lubricant, the sample deformation is homogeneous up to strains of 1.5. Tests carried out on 5xxx and 6xxx alloys to evaluate the stress-strain relations show that a generalized Voce law gives a good quantitative fit for the data. ii) for high temperature plate processing, quantitative flow stress data can be obtained up to 500°C with a rapid quench using a hot channel-die set-up. Some new results are presented here for high strain hot PSC tests on Al-Mn and Al-Mg alloys together with microstructure analyses.

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