Dynamic recrystallization kinetics and microstructure evolution of 7055 aluminum alloy during hot compression

2019 ◽  
Vol 116 (6) ◽  
pp. 605
Author(s):  
Tao Zhang ◽  
Huapu Sha ◽  
Lei Li ◽  
Shihong Lu ◽  
Hai Gong
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Grain Refinement ◽  
Microstructure Evolution ◽  
Large Strain ◽  
Small Strain ◽  
Small Strain Rate ◽  
7055 Aluminum Alloy

7055 aluminum alloy is widely used in manufacture of key components in fields of aerospace. Hot forming is the vital process for manufacture of components. Dynamic recrystallization (DRX) plays a significant role in grain refinement. Hot compressions and metallographic tests are conducted. Equations of DRX kinetics are fitted by least square method and finite element models (FEM) coupled with DRX kinetics equations are established to study the effects of forming parameters on microstructure evolution. The results show that true stress increases with ascending strain rate and decreases with ascending temperature. Large strain, small strain rate and high temperature are beneficial to sufficient DRX fraction and grain refinement. Deformation energy and thermally activated motion of atoms and molecules resulting from large strain and high temperature contribute to dynamic nucleation; meanwhile, small strain rate provides sufficient time for growth of recrystallized grains. The FEM results agree with experiments.

Static recrystallization kinetics and microstructure evolution of 7055 aluminum alloy

2019 ◽  
Vol 116 (1) ◽  
pp. 120
Author(s):  
Tao Zhang ◽  
Lei Li ◽  
Shihong Lu ◽  
Zhengfang Li ◽  
Peng Chen ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Microstructure Evolution ◽  
Static Recrystallization ◽  
Large Strain ◽  
Processing Parameters ◽  
Temperature Sensitive ◽  
Sensitive Material ◽  
Interval Time ◽  
7055 Aluminum Alloy

In order to acquire flow characteristics in multi-pass hot plastic deformation and the optimized processing parameters for 7055 aluminum alloy, the double-pass hot compressive flow stress behavior was studied at the temperatures from 300 to 420 °C, the strain from 0.2 to 0.4 and the pass interval time from 10 to 100s on Gleeble-3180 thermo-simulation machine. The static recrystallization (SRX) kinetics and grain size model of 7055 aluminum alloy were acquired by regression analysis. The metallographic tests were conducted and the effects of pass interval time, temperature and strain on microstructure evolution of SRX were analyzed. The results show that 7055 aluminum alloy is temperature sensitive material and the yield flow stress decreases with ascending temperature and pass interval time. Large strain, high temperature and long pass interval time are beneficial to larger SRX fraction and grain refinement. The investigation of flow characteristic and microstructure evolution can be a guidance to acquire optimized processing parameters for multi-pass hot deformation of 7055 aluminum alloy.

Grain Evolution Character of Discal Parts by Roll Forming

2013 ◽  
Vol 749 ◽  
pp. 328-336
Author(s):  
Quan Lin Jin
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Titanium Alloy ◽  
Aluminum Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Grain Refinement ◽  
Grain Growth ◽  
Roll Forming ◽  
Alloy 6061

A study on grain evolution character of discal parts roll forming was carried out by means of experiment and numerical simulation. The discal part material is aluminum alloy 6061 and titanium alloy TC4. The roll forming temperature is 480-500 and 930-1020 for aluminum alloy 6061 and titanium alloy TC4, respectively. A digital double-sided roll forming machine was used for roll forming experiment of discal parts. The high frequency induction heating was used for disk heating, where the deformation zone is in the state of constant temperature. A numerical simulation of roll forming of the 6061 aluminum alloy disk was carried out. The simulated results include macroscopic deformation and various grain size evolution variables. The dynamic recrystallization, the dynamic and static grain growth were considered in the numerical simulation. The experimental and simulated results showed that there may appear not only the grain refinement due to dynamic recrystallization but also dynamic and static grain growth. It is different that from discal parts integrally forging there are the largest deformation, the highest strain rate and the best recrystallization and grain refinement in the zones contacted with the roll tools. In the zones far from the rollers, the strain rate is very low and average grain size increases until once again contact to the rollers and start new grain refinement.

Flow behavior and microstructure evolution of 7055 aluminum alloy impacted at high strain rates

2016 ◽  
Vol 677 ◽  
pp. 203-210 ◽  
Author(s):  
Shengdan Liu ◽  
Shaoling Wang ◽  
Lingying Ye ◽  
Yunlai Deng ◽  
Xinming Zhang
Keyword(s):  
Aluminum Alloy ◽  
Microstructure Evolution ◽  
High Strain ◽  
Flow Behavior ◽  
Strain Rates ◽  
High Strain Rates ◽  
7055 Aluminum Alloy

Effect of deformation induced precipitation on grain refinement and improvement of mechanical properties AA 7055 aluminum alloy

2017 ◽  
Vol 130 ◽  
pp. 123-134 ◽  
Author(s):  
Jinrong Zuo ◽  
Longgang Hou ◽  
Jintao Shi ◽  
Hua Cui ◽  
Linzhong Zhuang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Grain Refinement ◽  
7055 Aluminum Alloy

An Explanation of the Small Strain-Rate Sensitivity of Ni3Al

1996 ◽  
Vol 460 ◽  
Author(s):  
Y. Q. Sun
Keyword(s):  
Strain Rate ◽  
Yield Stress ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Propagation Speed ◽  
Small Strain ◽  
Small Strain Rate

ABSTRACTBased on the superkink model, an explanation is given in this paper for the small strain-rate sensitivity of the anomalous yield stress of Ni3Al. The yield stress is proposed to be the stress needed to destabilise the average superkinks and it varies inversely with superkink height. The yield stress is insensitive to the strain-rate because the superkink height is controlled by the rate at which the superkink widens and is not directly related with the superkink propagation speed.

Microstructure and Plasticity of Hot Deformed 5083 Aluminum Alloy Produced by Rapid Solidification and Hot Extrusion / Badania Mikrostruktury I Plastyczności Odkształcanego Na Gorąco Szybko-Krystalizowanego I Wyciskanego Stopu Aluminium 5083

2012 ◽  
Vol 57 (4) ◽  
pp. 1253-1259 ◽  
Author(s):  
T. Tokarski ◽  
Ł. Wzorek ◽  
H. Dybiec
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Temperature Range ◽  
Rapidly Solidified ◽  
5083 Aluminum Alloy ◽  
Conventionally Cast

The objective of the present study is to analyze the mechanical properties and thermal stability for rapidly solidified and extruded 5083 aluminum alloy (RS). Compression tests were performed in order to estimate flow stress and strain rate sensitivity relation for 5083 alloy in the temperature range of 20°C to 450°C. For the comparison purposes, conventionally cast and extruded industrial material (IM) was studied as well. Deformation tests performed at room temperature conditions show that rapidly solidified material exhibits about 40% higher yield stress (YS=320 MPa) than conventionally cast material (YS=180 MPa), while the deformation at 450°C results in significant decrease of flow stress parameters for RS material (YS=20 MPa) in comparison to IM material (YS=40 MPa). Strain rate sensitivity parameter determined for high temperature conditions indicates superplasticity behavior of RS material. Structural observations show that under conditions of high-temperature deformation there are no operating recrystallization mechanisms. In general, grain size below 1µm and size of reinforcing phases below 50 nm is preserved within the used deformation temperature range.

Sign in / Sign up

Export Citation Format

Share Document