Effect of Homogenization on Recrystallization of Twin Roll Cast AA3003 Alloy

2013 ◽  
Vol 404 ◽  
pp. 122-126
Author(s):  
Yi You Tu ◽  
De Zhong Zhang
Keyword(s):  
Annealing Temperature ◽  
Volume Fraction ◽  
Resistivity Measurement ◽  
Optical Microscope ◽  
Intermetallic Particles ◽  
Temperature Homogenization ◽  
Homogenization Temperatures ◽  
Twin Roll Cast ◽  
Twin Roll ◽  
Electric Resistivity Measurement

The effect of homogenizations on the recrystallization microstructure of as-rolled twin roll cast AA3003 alloy were investigated using optical microscope, scanning electron microscopy and electric resistivity measurement. The results indicate that high temperature homogenization significantly decrease the supersaturation of Mn in the alloy, and both the volume fraction and the diameter of intermetallic particles increase as the homogenization temperatures. The shape of the recrystallized grains changes from pancake-like to equiaxed, as the annealing temperature increases above 520°C.

Eutectoid Decomposition of δ-Ferrite in Ferritic-Austenitic Duplex Cast Steel - Structural and Morphological Study

2012 ◽  
Vol 706-709 ◽  
pp. 2314-2319 ◽  
Author(s):  
D. Dyja ◽  
Z. Stradomski ◽  
Cezary Kolan ◽  
Grzegorz Stradomski
Keyword(s):  
Annealing Temperature ◽  
Volume Fraction ◽  
Cast Steel ◽  
Optical Microscope ◽  
Rapid Progress ◽  
Phase Precipitation ◽  
X Ray ◽  
Σ Phase ◽  
Δ Ferrite ◽  
Surface Development

The influence of time and temperature of ageing on the σ-phase morphology in ferritic-austenitic cast steel have been investigated in this study. The morphology and quantity of the σ-phase were analyzed by using optical microscope, X-ray diffractometry, scanning electron microscope and image analysis, respectively. The annealing temperature has a significant influence on the morphology, volume fraction and the dynamics of σ-phase precipitation. Surface development of the σ-phase decreases from R=4.3, for the cast steel annealed at 700°C to R=2.4 for the cast steel annealed at 900°C, and the volume fraction Vvσ from 50.8% to 26.5%, respectively. The most rapid progress of δ → σ + γ’ transformation was observed at 800°C.

scholarly journals Microstructure and Hot Workability of Twin-roll Cast Dispersoid-strengthened Al- Mg-Si-Mn alloys

2021 ◽  
Author(s):  
Xiaoming Qian ◽  
Yu Zhang ◽  
Zhaodong Wang ◽  
X.-Grant Chen ◽  
Yong Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Solution Concentration ◽  
Strengthening Effect ◽  
Hot Workability ◽  
Compression Tests ◽  
Free Zone ◽  
Intermetallic Particles ◽  
Roll Casting ◽  
Temperature Homogenization ◽  
Twin Roll

Abstract Dispersoid-strengthened Al-Mg-Si-Mn aluminum alloys were produced by twin-roll casting (TRC) and conventional mold casting (MC). An extra-low temperature homogenization was performed at temperature of 430 °C for 6 h, which was followed by uniaxial hot compression tests. The results showed that the as-cast TRC samples had a lower eutectic fraction with a smaller size and a higher solid solution concentration compared to the as-cast MC samples. During the extra-low temperature homogenization, a large number of α-Al(Fe, Mn)Si dispersoids precipitated, and the dispersoids in the TRC sample had a greater number density than those in the MC sample. Precipitation-free zone (PFZ) formed near the eutectic regions, TRC sample had a lower PFZ fraction than that of MC sample. The TRC samples yielded higher flow stresses of hot deformation than MC sample owing to the stronger dispersoid strengthening effect. Severe edge cracking occurred in the deformed MC samples due to the high fraction of coarse AlFeMnSi intermetallic particles, no edge crack formed in the TRC samples owing to its lower fraction and fine intermetallics which improved the hot workability of TRC sample.

Dynamic Recrystallization Behaviour of Twin Roll Cast AZ31 Strips during Hot Deformation

2014 ◽  
Vol 622-623 ◽  
pp. 569-574 ◽  
Author(s):  
Madlen Ullmann ◽  
Matthias Schmidtchen ◽  
Rudolf Kawalla
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Volume Fraction ◽  
Az31 Alloy ◽  
Rolling Process ◽  
Recrystallization Process ◽  
Strain Rates ◽  
Compression Tests ◽  
Twin Roll Cast ◽  
Twin Roll

The recrystallization behaviour of a Twin Roll Cast AZ31 alloy, under deformation conditions corresponding to the initial stands of a magnesium hot rolling process, has been investigated. A set of strain levels, beginning at the critical strain for the onset of dynamic recrystallization has been studied. The dynamic recrystallization, taking place during hot deformation of magnesium alloy AZ31 is analyzed with help of plane strain compression tests conducted together with microscopic examination. Dynamically recrystallized volume fraction and size of dynamically recrystallized grains increase with increasing strain. When the strain is constant, the dynamically recrystallized volume fraction is higher at higher deformation temperatures or lower strain rates. Furthermore, it has been found out that deformation temperature plays a major role, rather than strain rates, in activating the dynamic recrystallization process during deformation. The results were used to identify the coefficients for the JMAK-model approach on the dynamic recrystallization of an AZ31 TRC-sheet.

Effects of Homogenization Conditions on the Microstructures of Twin-Roll Cast Foil Stock of AA8021 Aluminum Alloy

2016 ◽  
Vol 877 ◽  
pp. 296-302
Author(s):  
Wei Chen ◽  
Pi Zhi Zhao ◽  
Yu Li Zhou ◽  
Yan Feng Pan
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Foil ◽  
Grain Structure ◽  
Medium Temperature ◽  
Grain Structures ◽  
Temperature Homogenization ◽  
Twin Roll Cast ◽  
Twin Roll ◽  
Homogenization Condition

AA8021 aluminum alloy twin-roll cast strips with 7mm gauge were rolled to 3.8mm gauge sheets and given homogenization, further rolled into 0.55mm gauge foil stocks with intermediate annealing. This paper investigated the influence of homogenization conditions on microstructures of foil stocks in detail. The results show that, for the foil stock made from the sheet without homogenization, the grain structure is partially recrystallized. While the grain structure of foil stock made from the sheet with medium temperature homogenization is fully recrystallized, but it is coarse near sheet surface. However, foil stock made from the sheet with high temperature homogenization has fine and uniform recrystallized grain structures. The differences of grain structures among these three kinds of foil stocks can be understood by the variation in solid solution content of Fe, Si, Mn and distribution of intermetallic compounds. The optimized homogenization condition was adopted by our plant to produce foil stock, and its grain structure was fine and uniform. The surface quality of final aluminum foil rolled from the foil stock could meet high grade requirements of customers.

scholarly journals Microstructural Characterization and Mechanical Properties of Ti-6Al-4V Alloy Subjected to Dynamic Plastic Deformation Achieved by Multipass Hammer Forging with Different Forging Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xiurong Fang ◽  
Jiang Wu ◽  
Xue Ou ◽  
Fuqiang Yang
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Optical Microscope ◽  
Strain Rates ◽  
Materials Properties ◽  
Forging Process ◽  
Hammer Forging ◽  
Dynamic Plastic Deformation

Dynamic plastic deformation (DPD) achieved by multipass hammer forging is one of the most important metal forming operations to create the excellent materials properties. By using the integrated approaches of optical microscope and scanning electron microscope, the forging temperature effects on the multipass hammer forging process and the forged properties of Ti-6Al-4V alloy were evaluated and the forging samples were controlled with a total height reduction of 50% by multipass strikes from 925°C to 1025°C. The results indicate that the forging temperature has a significant effect on morphology and the volume fraction of primary α phase, and the microstructural homogeneity is enhanced after multipass hammer forging. The alloy slip possibility and strain rates could be improved by multipass strikes, but the marginal efficiency decreases with the increased forging temperature. Besides, a forging process with an initial forging temperature a bit above β transformation and finishing the forging a little below the β transformation is suggested to balance the forging deformation resistance and forged mechanical properties.

scholarly journals Analysis of defects in a twin roll cast Mg‐Y‐Zn magnesium alloy

2021 ◽  
Author(s):  
Kristina Kittner ◽  
Madlen Ullmann ◽  
Falko Arndt ◽  
Susanne Berndorf ◽  
Thorsten Henseler ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Twin Roll Cast ◽  
Twin Roll

Size-Dependent Interdiffusion in Nanomaterials

2005 ◽  
Vol 101-102 ◽  
pp. 123-130 ◽  
Author(s):  
Lyudmila N. Paritskaya ◽  
Yuri S. Kaganovsky ◽  
V.V. Bogdanov
Keyword(s):  
Grain Growth ◽  
Volume Fraction ◽  
Bulk Diffusion ◽  
Solution Concentration ◽  
Lattice Parameter ◽  
Structural Element ◽  
Size Dependent ◽  
Second Stage ◽  
Temperature Homogenization ◽  
Two Stages

The phenomenon of low-temperature homogenization (LTH) during interdiffusion is studied under condition a t Dv £ 2 / 1 ) ( (Dv is the bulk diffusion coefficient, a is the lattice parameter) using nano-objects of binary Cu-Ni and Cr-Ni systems compacted from nano-powders and produced by mechanical alloying. Two stages of LTH were detected: at the first stage (t £ 103 s) the volume fraction of solution rapidly grows; at the second stage (t > 103 s) the volume fraction of solutions grows slowly with practically constant average solution concentration. The first stage of LTH correlates with active grain growth caused by small size (l) of structural element and nonequilibrium structure of nano-objects. Obtained results are analyzed theoretically in terms of interdiffusion along migrating GBs due to grain growth at the first stage and DIGM mechanism at the second stage. It is shown that the GB concentration distribution during interdiffusion along migrating GBs and the kinetics of LTH depend on a parameter l/l where 2 / 1 ) / ( b b V sD d l= is the characteristic diffusion length. The mechanisms and criteria of LTH are proposed.

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