Homogenization of AlSi7MgCu0.5 Alloy as-Cast Structure by ECAP Processing

2014 ◽  
Vol 782 ◽  
pp. 390-393 ◽  
Author(s):  
Miloš Matvija ◽  
Martin Fujda ◽  
Marek Vojtko ◽  
Robert Kočiško

The homogenization of AlSi7MgCu0.5 alloy as-cast structure by using an equal channel angular pressing (ECAP) was investigated. The heat treatment of as-cast alloy applied before ECAP processing was required to increase alloy plasticity. Therefore, the samples of analyzed alloy were solution annealed at temperature of 550 °C for 4 hours and subsequently water quenched. Quenched samples were artificially aged at temperature of 300 °C for 5 hours to obtain an over-aged alloy state. The solution annealing of as-cast alloy state caused a partial spheroidization and coarsening of eutectic Si-particles. During artificial aging of analyzed alloy, the incoherent particles precipitated uniformly from α-solid solution. The ECAP technique at room temperature homogenized its heterogeneous dendritic microstructure and formed the ultra-fine grains of solid solution. A redistribution and fragmentation of the eutectic Si-particles and precipitated particles was occurred.

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Miloš Matvija ◽  
Martin Fujda ◽  
Ondrej Milkovič ◽  
Marek Vojtko ◽  
Róbert Kočiško ◽  
...  

The changes in the microstructure and improvement in the mechanical properties of as-cast AlSi7MgCu0.5 alloy induced by the heat treatment and technique of equal channel angular pressing (ECAP) were investigated. The heat treatment of as-cast alloy performed before the ECAP technique was required to increase the plasticity of the alloy. Therefore, the samples of analysed alloys were solution annealed at optimized temperature of 823 K for 4 hours to dissolve the particles of intermetallicπ(Al8FeMg3Si6) phase and to spheroidize the Si particles. Subsequently, water quenching and artificial ageing at optimized temperature of 573 K for 5 hours was used to obtain an overaged alloy state. The microstructure of alloy was consisted ofα(Al) solid solution, eutectic Si particles, and intermetallicβ(Mg2Si), Q-Al4Mg5Si4Cu,α-Al12(Fe,Mn)3Si, and/orα-Al15(Fe,Mn)3Si2phase particles. The crystal structure of present phases was confirmed by hard X-ray diffraction at Deutsches Elektronen-Synchrotron (DESY) in Hamburg and by the selected area electron diffraction (SAED) performed inside the transmission electron microscope (TEM). The heat-treated alloy was processed by ECAP at room temperature following route A. Repetitive ECAP of alloy homogenized the heterogeneous as-cast microstructure and formed the ultrafine subgrain microstructure with elongated subgrains of 0.2 µm in width and 0.65 µm in length and the high dislocation density. Microstructural changes in alloy induced by both heat treatment and ECAP led to the high strain hardening of the alloy that appeared in an improvement in strength, ductility, and microhardness of alloy in comparison with as-cast alloy state.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 607
Author(s):  
A. I. Alateyah ◽  
Mohamed M. Z. Ahmed ◽  
Yasser Zedan ◽  
H. Abd El-Hafez ◽  
Majed O. Alawad ◽  
...  

The current study presents a detailed investigation for the equal channel angular pressing of pure copper through two regimes. The first was equal channel angular pressing (ECAP) processing at room temperature and the second was ECAP processing at 200 °C for up to 4-passes of route Bc. The grain structure and texture was investigated using electron back scattering diffraction (EBSD) across the whole sample cross-section and also the hardness and the tensile properties. The microstructure obtained after 1-pass at room temperature revealed finer equiaxed grains of about 3.89 µm down to submicrons with a high density of twin compared to the starting material. Additionally, a notable increase in the low angle grain boundaries (LAGBs) density was observed. This microstructure was found to be homogenous through the sample cross section. Further straining up to 2-passes showed a significant reduction of the average grain size to 2.97 µm with observable heterogeneous distribution of grains size. On the other hand, increasing the strain up to 4-passes enhanced the homogeneity of grain size distribution. The texture after 4-passes resembled the simple shear texture with about 7 times random. Conducting the ECAP processing at 200 °C resulted in a severely deformed microstructure with the highest fraction of submicron grains and high density of substructures was also observed. ECAP processing through 4-passes at room temperature experienced a significant increase in both hardness and tensile strength up to 180% and 124%, respectively.


2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev

The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is higher than that achieved after conventional processing. Prior ECAP solution treatment and post-ECAP ageing can additionally increase the strength of the 6061 alloy. Under optimal ageing conditions a yield strength (YS) of 434 MPa and am ultimate tensile strength (UTS) of 470 MPa were obtained for the alloy. Additional cold rolling leads to a YS and UTS of 475 and 500 MPa with 8% elongation. It was found that the post-ECAP isothermal rolling of the 1560 alloy resulted in the formation of a nano-fibred structure and a tensile strength (YS = 540 MPa and UTS = 635 MPa) that has never previously been observed in commercial non-heat treatable alloys.


2011 ◽  
Vol 335-336 ◽  
pp. 783-786
Author(s):  
Fu Yin Han ◽  
Lin Hai Tian ◽  
Hong Xia Wang ◽  
Wei Liang ◽  
Wen Xian Wang

Sr added ignition-proof AZ91D-0.3Be magnesium alloy was prepared. The influence of Sr content on microstructure and mechanical properties of the alloy was studied. Results show that the microstructure of ignition-proof AZ91D-0.3Be magnesium alloy is refined by a small amount of Sr addition. It is due to that the enrichment of a few Sr atoms in solid liquid interface in the process of magnesium alloy solidification inhibits grain growth and accelerates more nucleation. However, with increasing of Sr addition the microstructure is coarsened. By 0.01% Sr addition the tensile strength of as-cast experimental alloy is increased by about 25% and that of both the solid-solution and aged alloy is increased by about 40%. The elongation of as-cast alloy is increased by about 20% and that of solid-solution alloy increased by about 30%.


2010 ◽  
Vol 667-669 ◽  
pp. 731-736 ◽  
Author(s):  
Irina P. Semenova ◽  
Alexander Medvedev

This work presents the possibility of strength enhancement in the -alloy Ti-6.8Mo-4.5Fe-1.5Al via equal channel angular pressing at room temperature without precipitation of a secondary -phase. Influence of the initial structure of the alloy and ageing temperature on the density of precipitations and dimensions of the secondary -phase is revealed. It has been stated that combination of the solid solution treatment with the subsequent ECAP processing and final ageing is an effective way to achieve superior strength and ductility.


2016 ◽  
Vol 56 (5) ◽  
pp. 353-359 ◽  
Author(s):  
Anna Lišková ◽  
Petra Lacková ◽  
Mária Mihaliková ◽  
Róbert Kočiško

This paper reports on an experiment to assess the influence of plastic deformation on the microstructure and properties of EN AW 6012 (AlMgSiPb) aluminium alloy in two states. The first was the initial state with heat treatment T3, and the second was the state after intensive plastic deformation by ECAP (Equal Channel Angular Pressing) technology. The ECAP process was carried out repeatedly at room temperature. In the initial state of the alloy, the process redistributed eutectic Si-particles and increased the strength of the alloy. The mechanical properties and the hardness increased due to intensive plastic deformation (the yield strength increased by 15%, the tensile strength by 6%, and the hardness by 23%). The fracture cracks initiated and propagated mainly along eutectic particles. The fracture area of the ECAPed specimen displayed a typical ductile cavity characteristic.


2013 ◽  
Vol 745-746 ◽  
pp. 321-326 ◽  
Author(s):  
Wei Wei ◽  
Kun Xia Wei ◽  
Igor V. Alexandrov ◽  
Fei Wang ◽  
Jing Hu

The composite filament structure was produced in the Cu-5.7%Cr and Cu-12.4%Cr as-cast alloy ingots by using equal channel angular pressing (ECAP) at room temperature. Optical and TEM microstructure, micro-hardness, tensile strength and electrical conductivity of ECAPed samples were investigated. The rotation and spreading of Cr particles took place during ECAP, and resulted in long thin in-situ filaments. The tensile strength increased with the number of the ECAP passes. A strengthening model was recommended to predict the enhancement of the tensile strength in Cu-Cr in situ fibrous composites.


2018 ◽  
Vol 913 ◽  
pp. 77-82 ◽  
Author(s):  
Ting Biao Guo ◽  
Qi Li ◽  
Chen Wang ◽  
Shi Ru Wei ◽  
Yi Bo Wu

The evolution of microstructure of ZL205A alloy during equal channel angular pressing (ECAP) by route A at room temperature was investigated by OM, SEM and XRD, and the hardness of cast and heat treatment alloy from different strain were tested. The results showed that the grain of cast alloy were obviously refined, the massive q phase along the grain boundary were crushed, and prompts the distribution of q streamline after one pass through ECAP. After two passes of ECAP, the distribution of q phase is more uniform. After heat treatment through ECAP, the grains were also obviously refined, and elongated in axial direction, which also prompts the distribution of q streamline. The hardness was significantly improved after ECAP. The hardness of cast alloy increases from 65HV to 132HV after two passes, and that of heat treatment alloy increases from 112HV to 198HV. With the increase of extrusion passes, the number of dimples gradually increased and evenly distributed, the depth of dimples was of a similar level, and the distribution of precipitated phase is more uniform.


2011 ◽  
Vol 189-193 ◽  
pp. 943-948
Author(s):  
Tao Song ◽  
Xiao Jing Xu ◽  
Zhen Fan ◽  
Yong Luo ◽  
Bin Wang ◽  
...  

Equal channel angular pressing (ECAP) of 3003Al ingot has been performed at room temperature, with an imposed equivalent strain of ~0.5 for single pass, and the refinement/distribution of inclusions and the hardness/dislocation of the alloy were examined. The results show that the first pass ECAP processing refined the inclusions (AlFe (Mn)Si) of the alloy considerably, with the size variation from 5-15μm length/1-2μm width to 1-3μm length/1-2μm width. In addition to the refinement, the first pass ECAP processing improved significantly the distribution of the AlFe(Mn)Si inclusions, and introduced high density of dislocations, leading to ~66.7 % increase of hardness. It was found that with the increase of number of ECAP processing passes, the distribution of AlFe(Mn)Si inclusions were increasingly more uniform, while the size of inclusions, the hardness and dislocation density (dislocation strengthening) of the alloy kept almost unchanged. The present results demonstrate the possibility of ECAP as an effective tool to refine AlFe(Mn)Si inclusions of aluminum alloys.


2010 ◽  
Vol 129-131 ◽  
pp. 942-946 ◽  
Author(s):  
Jun Zhao ◽  
Hong Yan Zhai ◽  
Han Zhang ◽  
Xiang Nan Wu ◽  
Guo Xing Pang ◽  
...  

An ultrafine microduplex structure was successfully produced through equal channel angular pressing (ECAP) at ambient temperature. According to the morphological characteristics of cementite lamellas, the deformed pearlite consists of shear break lamella, locally thinned lamella and irregularly bent lamella. The proportion of locally thinned lamella and irregularly bent lamella has increased with the pass number of ECAP. In addition, the deformed pearlitic ferrite became a supersaturated solid solution of carbon due to the partial dissolution of cementite during ECAP.


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