The Effect of Strain Rate History on the Dynamic Grain Growth Behaviour of AA 5083

2007 ◽  
Vol 551-552 ◽  
pp. 627-632
Author(s):  
B. Zhang ◽  
Pete S. Bate ◽  
Norman Ridley
Keyword(s):  
Strain Rate ◽  
Grain Growth ◽  
Significant Influence ◽  
Mechanical Behaviour ◽  
Strain Rates ◽  
Growth Behaviour ◽  
Superplastic Behaviour ◽  
Dynamic Grain Growth

Dynamic grain growth in superplastic AA5083 deformed at constant strain rates and varying strain rates has been studied. It has been found that the strain rate history has a significant influence on the grain growth behaviour. It is proposed that differences in mechanical behaviour of AA5083 for the strain rate conditions examined can be attributed to differences in the grain growth behaviour. The influence of dynamic grain growth on the superplastic behaviour of AA5083 is discussed.

Superplastic Behaviour of AA5083 Aluminium Alloy with Scandium and Zirconium

2012 ◽  
Vol 706-709 ◽  
pp. 395-401 ◽  
Author(s):  
A. Smolej ◽  
B. Skaza ◽  
B. Markoli ◽  
Damjan Klobčar ◽  
V. Dragojević ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Wide Temperature Range ◽  
Initial Strain Rate ◽  
Initial Strain ◽  
Strain Rates ◽  
Superplastic Behaviour ◽  
Hot And Cold Rolling ◽  
Superplastic Properties

The aim of the present investigation was to determine and to compare the superplastic behaviour of the AA5083 (Al-Mg-Mn) alloy with Sc and Zr additions. The investigated alloys were processed to form sheets by conventional hot and cold rolling. The superplastic properties were determined with strain rates in the range of 1x10-4to 5x10-2s-1and forming temperatures of 350 to 550°C. The results showed that the alloy with about 0.4% Sc exhibited a high superplastic ductility across a wide temperature range and strain rates up to 1x10-2s-1. The highest elongations to failure of about 2000% were attained at 550°C and at an initial strain rate of 5x10-3s-1. However, the alloy with about 0.15% Zr exhibited elongations up to 600%. The FSP processed Al-4.5Mg alloy with combined addition of about 0.2% Sc and 0.15% Zr exhibited good superplastic properties at higher strain rates (> 1x10-2s-1) with elongations up to 1500%.

scholarly journals Mechanical behaviour and structure of snow under uniaxial tensile stress

1980 ◽  
Vol 26 (94) ◽  
pp. 275-282 ◽  
Author(s):  
Hidek Narita
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Maximum Strength ◽  
Ductile Deformation ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Thin Sections ◽  
Uniaxial Tensile Stress ◽  
Small Cracks

AbstractThe mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10–8to 3.1 × 10–4ms–1and snow density 240-470 kg m–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10–5s–1, the maximum strength increased with decreasing strain-rate but below 10–5s–1it decreased with decreasing strain-rate.

Superplasticity in a 5024 Aluminium Alloy Processed by Severe Plastic Deformation

2012 ◽  
Vol 735 ◽  
pp. 353-358 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Tagirova ◽  
Rustam Kaibyshev
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Initial Strain Rate ◽  
Strain Rates ◽  
Superplastic Behaviour ◽  
Angular Pressing ◽  
Elongation To Failure ◽  
Zr Alloy

The superplastic behaviour of an Al-4.6%Mg-0.35%Mn-0.2%Sc-0.09%Zr alloy was studied in the temperature range 250-500°C at strain rates ranging from 10-4 to 10-1 s-1. The AA5024 was subjected to equal channel angular pressing (ECAP) at 300°C up to ~12. The highest elongation-to-failure of ∼3300% was attained at a temperature of 450°C and an initial strain rate of 5.6×10-1 s-1. Regularities of superplastic behaviour of the 5024 aluminium alloy are discussed.

scholarly journals Mechanical behaviour and structure of snow under uniaxial tensile stress

1980 ◽  
Vol 26 (94) ◽  
pp. 275-282 ◽  
Author(s):  
Hidek Narita
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Maximum Strength ◽  
Ductile Deformation ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Thin Sections ◽  
Uniaxial Tensile Stress ◽  
Small Cracks

AbstractThe mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10–8 to 3.1 × 10–4 ms–1 and snow density 240-470 kg m–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10–5 s –1, the maximum strength increased with decreasing strain-rate but below 10–5 s–1 it decreased with decreasing strain-rate.

Strain Rate Effect on Microstructure of Dynamically Compressed Magnesium Alloy AZ31B

2013 ◽  
Vol 535-536 ◽  
pp. 137-140 ◽  
Author(s):  
Iram Raza Ahmad ◽  
Muhammad Syfiqu ◽  
Xiao Jing ◽  
Dong W. Shu
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Fuel Consumption ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Microstructural Analysis ◽  
Strain Rate Effect ◽  
Strain Rates ◽  
Magnesium Alloy Az31b ◽  
Protective Structures

Lightweight materials have been in focus in recent times for their use in automobiles, planes and protective structures for numerous benefits ranging from reduction in fuel consumption and increased payload in vehicles to lighter and stronger protective structures. For efficient use of materials in applications where they are subjected to unusual higher sudden loads, it is necessary to understand their mechanical behaviour under such conditions.In present study, the effect of strain rate on deformation of magnesium alloy AZ31Bunder compression has been investigated. The alloy is subjected to various strain rates as 10-4s-1, 500s-1 and 2500s-1 and the microstructural analysis was performed to see the changes in the microstructure of the alloy and their effect on the mechanical response of the alloy is portrayed.

The Effect of Copper Content on the Dynamic Grain Growth in AL-Cu-Zr Systems

2007 ◽  
Vol 558-559 ◽  
pp. 803-809 ◽  
Author(s):  
Kasra Sotoudeh ◽  
Pete S. Bate ◽  
John F. Humphreys
Keyword(s):  
Strain Rate ◽  
Grain Growth ◽  
Copper Content ◽  
Texture Evolution ◽  
Uniaxial Tensile ◽  
Sensitivity Index ◽  
High Angle ◽  
Initial Microstructure ◽  
Dynamic Grain Growth ◽  
Effect Of Copper

The effect of copper content on dynamic grain growth in Al-Cu-Zr system was investigated by studying the microstructural development and texture evolution during uniaxial tensile deformation of Al-2wt%Cu-0.3wt.%Zr and Al-4wt%Cu-0.4wt.%Zr alloys at 450°C with a strain rate of 10-3s-1, with a similar initial microstructure in both materials. The initial microstructure consisted of layers of different orientations, the layers being separated by high-angle grain boundaries with low-angle boundaries separating grains within the layers. The initial grain spacing was about 5m and the texture was typical of rolled aluminium alloys. The 4wt.%Cu alloy gave a higher strain rate sensitivity index, m, and a greater ductility compared to the low copper content alloy. An increase in grain size occurred in both materials due to deformation, but this dynamic grain growth (DGG) was much greater in the material with the higher copper content. This was associated with a more rapid conversion of low-angle boundaries to high angle ones in the 4wt%Cu material which is consistent with changes in crystallographic texture occurring during deformation.

The Abnormal Grain Growth of P/M Nickel-Base Superalloy: Strain Storage and CSL Boundaries

2014 ◽  
Vol 1064 ◽  
pp. 49-54 ◽  
Author(s):  
Shuang Fang ◽  
Yun Peng Dong ◽  
Shu Yun Wang
Keyword(s):  
Strain Rate ◽  
Grain Growth ◽  
Deformation Temperature ◽  
True Strain ◽  
Compressive Force ◽  
Constant Strain Rate ◽  
Nickel Base Superalloy ◽  
Strain Rates ◽  
Nickel Base ◽  
Base Superalloy

The Nickel-base superalloy samples were prepared by the isothermal forging in different strain rates at 1070°C. The isothermal deformation tests were carried out at constant strain rate in a vacuum environment using the Thermecmastor (Fuji Electronic Industrial Co., Japan) with a capacity of 30 ton compressive force. All the samples were deformed to a true strain of 1.04 at deformation temperature 1070°C and strain rate 0.001s-1~0.1s-1 respectively. The result is The deformation strain rate determine the position and domain of AGG and the temperature determine the severity of AGG by deformation temperature and temperature rise. The most serious region of AGG is related to the specific CSL boundaries. The fraction of Ʃ3 boundary reaches the peak point value and fraction of Ʃ7 boundary reaches the valley point value in all the samples with different strain rates. The most serious region of AGG is also related to the residual strain. In the most serious region of AGG, more dislocation is used to prefer grain growth to recrystallization, which can refine grain.

Instability of Superplastic Aluminium Alloys

1990 ◽  
Vol 196 ◽  
Author(s):  
H. Iwasaki ◽  
S. Hayami ◽  
K. Higashi ◽  
S. Tanimura
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
Grain Growth ◽  
Aluminium Alloys ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Plastic Instability ◽  
Small Magnitude ◽  
Instability Parameter ◽  
Dynamic Grain Growth

ABSTRACTThe influence of the strain hardening coefficient,γ,and the strain rate sensitivity exponent, m, on the onset and growth of necking has been pointed out in many models about plastic instability controlled by the mechanical properties of materials. In this paper, the instability parameter I (=(l-γ-m)/m) proposed by Hart is used to relate the values of m (=∂lnσ/∂lnέ) and γ (=∂σ/(σ·∂ε)) for some superplastic aluminium alloys. These values of m and γ were calculated from the load-elongation curve at various strain-rates in constant strain-rate tests with periodic m determinations by strain-rate departures of small magnitude. It will be shown that the strain hardening due to grain growth contributes to an increase in the stability of plastic deformation during superplastic flow. However the decrease of m due to dynamic grain growth with strain causes superplastic deformation to be unstable near the onset of fracture. The transition of I values from negative to positive coincides with a decrease in m value and flow stress.It is concluded that the development of necks can be characterized by an instability parameter I which include the effect of strain hardening caused by strain induced grain growth.

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