scholarly journals Microstructure Changes and Improvement in the Mechanical Properties of As-Cast AlSi7MgCu0.5 Alloy Induced by the Heat Treatment and ECAP Technique at Room Temperature

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Miloš Matvija ◽  
Martin Fujda ◽  
Ondrej Milkovič ◽  
Marek Vojtko ◽  
Róbert Kočiško ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Room Temperature ◽  
Cast Alloy ◽  
Artificial Ageing ◽  
Angular Pressing ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Alloy State ◽  
Eutectic Si

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.

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
Keyword(s):  
Solid Solution ◽  
Room Temperature ◽  
Cast Alloy ◽  
Aged Alloy ◽  
Dendritic Microstructure ◽  
Ecap Processing ◽  
Cast Structure ◽  
Angular Pressing ◽  
Alloy State ◽  
Eutectic Si

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.

scholarly journals Achievement of High Strength and Ductility in Al–Si–Cu–Mg Alloys by Intermediate Phase Optimization in As-Cast and Heat Treatment Conditions

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 647 ◽  
Author(s):  
Bingrong Zhang ◽  
Lingkun Zhang ◽  
Zhiming Wang ◽  
Anjiang Gao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Intermediate Phase ◽  
High Strength ◽  
Mg Alloys ◽  
Artificial Ageing ◽  
Treatment Conditions ◽  
Eutectic Si

In order to obtain high-strength and high-ductility Al–Si–Cu–Mg alloys, the present research is focused on optimizing the composition of soluble phases, the structure and morphology of insoluble phases, and artificial ageing processes. The results show that the best matches, 0.4 wt% Mg and 1.2 wt% Cu in the Al–9Si alloy, avoided the toxic effect of the blocky Al2Cu on the mechanical properties of the alloy. The addition of 0.6 wt% Zn modified the morphology of eutectic Si from coarse particles to fine fibrous particles and the texture of Fe-rich phases from acicular β-Fe to blocky π-Fe in the Al–9Si–1.2Cu–0.4Mg-based alloy. With the optimization of the heat treatment parameters, the spherical eutectic Si and the fully fused β-Fe dramatically improved the ultimate tensile strength and elongation to fracture. Compared with the Al–9Si–1.2Cu–0.4Mg-based alloy, the 0.6 wt% Zn modified alloy not only increased the ultimate tensile strength and elongation to fracture of peak ageing but also reduced the time of peak ageing. The following improved combination of higher tensile strength and higher elongation was achieved for 0.6 wt% Zn modified alloy by double-stage ageing: 100 °C × 3 h + 180 °C × 7 h, with mechanical properties of ultimate tensile strength (UTS) of ~371 MPa, yield strength (YS) of ~291 MPa, and elongation to fracture (E%) of ~5.6%.

Strength of Commercial Aluminum Alloys after Equal Channel Angular Pressing and Post-ECAP Processing

2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloys ◽  
Ultimate Tensile Strength ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Solution Treatment ◽  
Ecap Processing ◽  
Angular Pressing

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.

scholarly journals Study of the precipitation hardening process in recycled Al-Si-Cu cast alloys

2017 ◽  
Vol 62 (1) ◽  
pp. 397-403 ◽  
Author(s):  
L. Kuchariková ◽  
E. Tillová ◽  
M. Matvija ◽  
J. Belan ◽  
M. Chalupová
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Precipitation Hardening ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Second Phase ◽  
Thin Foils ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Cast Alloys

AbstractThe formation of extremely small uniformly dispersed particles of a second phase within the original phase matrix during heat treatment changed material properties. Therefore the characterization of precipitation had been investigated using high resolution transmission electron microscopy (TEM) and electron diffraction of thin foils for an AlSi9Cu3 cast alloy. For investigation the hardening effect onto mechanical properties of aluminium cast was used heat treatment, which consisted from solution treatment at 515°C / 4 hours (h), followed by quenching into water with temperature 50°C and artificial aging using different temperatures 170°C and 190°C with different holding time 2, 4, 8, 16, and 32 hours. The observations of microstructure and substructure reveals that precipitation hardening has caused great changes in size, morphology and distributions of structural components, the formation of precipitates of Cu phases, and the change of mechanical properties as well.

Grain Refinement of Pure Copper by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 393-398 ◽  
Author(s):  
Nayar Lugo ◽  
Jose María Cabrera ◽  
Núria Llorca-Isern ◽  
C.J. Luis-Pérez ◽  
Rodrigo Luri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Grain Refinement ◽  
Strain Distribution ◽  
Room Temperature ◽  
Pure Copper ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Homogeneous Strain

Pure commercial Cu of 99,98 wt % purity was processed at room temperature by Equal- Channel Angular Pressing (ECAP) following route Bc. Heavy deformation was introduced in the samples after a considerable number of ECAP passes, namely 1, 4, 8, 12 and 16. A significant grain refinement was observed by transmission electron microscopy (TEM). Tensile and microhardness tests were also carried out on the deformed material in order to correlate microstructure and mechanical properties. Microhardness measurements displayed a quite homogeneous strain distribution. The most significative microstructural and mechanical changes were introduced in the first ECAP pass although a gradual increment in strength and a slight further grain refinement was noticed in the consecutive ECAP passes.

Influence of Ageing Heat Treatment on Microstructure and Mechanical Properties of a Secondary Rheocast AlSi9Cu3(Fe) Alloy

2015 ◽  
Vol 828-829 ◽  
pp. 212-218 ◽  
Author(s):  
Stefano Capuzzi ◽  
Giulio Timelli ◽  
Alberto Fabrizi ◽  
Franco Bonollo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Optical Microscope ◽  
Micro Hardness ◽  
Hardness Testing ◽  
Microscopy Technique ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Al Matrix

The effects of different process parameters (temperature and time) during the ageing treatment on the microstructure and the mechanical properties of a secondary rheocast AlSi9Cu3(Fe) alloy have been examined. Optical microscope investigations have been performed to qualitatively study the microstructure of the as-rheocast and thermal treated alloys. Transmission electron microscopy technique and selected area electron diffraction analyses have been used to characterize the hardening phases precipitated in the Al-matrix during the different ageing stages. The evolution of mechanical properties of the Al matrix has been monitored by micro-hardness testing.

Mechanical Properties of Different Coppers Processed by Equal Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 713-718 ◽  
Author(s):  
Oscar Fabián Higuera ◽  
Jairo Alberto Muñoz ◽  
Jose María Cabrera
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Angular Pressing ◽  
Cu Alloys ◽  
Ecap Process ◽  
First Pass ◽  
Annealing Heat Treatment

Mechanical properties of two Cu alloys (electrolytic and fire refined) severely deformed by equal channel angular pressing (ECAP) process were investigated. They were treated with a annealing heat treatment to 600°C during 30 minutes and then they were extruded in a Φ=90º ECAP die at room temperature following route Bc. Heavy deformation was introduced in the samples after a considerable number of ECAP passes from 1, 2, 3, 4, 5, 6, 7, 8, to 16. The principal changes were introduced in the first pass by ECAP but a gradual increment in the mechanical properties was observed for the consecutive ECAP passes. Also, the electrical conductivity decreased with increasing numbers of ECAP passes.

Effect of Equal Channel Angular Pressing on Microstructure and Mechanical Properties of ZL205A Alloy

2018 ◽  
Vol 913 ◽  
pp. 77-82 ◽  
Author(s):  
Ting Biao Guo ◽  
Qi Li ◽  
Chen Wang ◽  
Shi Ru Wei ◽  
Yi Bo Wu
Keyword(s):  
Heat Treatment ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Cast Alloy ◽  
Axial Direction ◽  
Angular Pressing ◽  
Precipitated Phase ◽  
Zl205a Alloy ◽  
Pass Through ◽  
Evolution Of Microstructure

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.

Microstructure Analysis of AlSi10MgMn Aluminium Cast Alloy

2014 ◽  
Vol 782 ◽  
pp. 365-368
Author(s):  
Mária Chalupová ◽  
Eva Tillová ◽  
Mária Farkašová
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Complex Geometry ◽  
Cast Alloy ◽  
Dynamic Properties ◽  
Intermetallic Phases ◽  
Age Hardening ◽  
Thin Walls ◽  
Eutectic Si ◽  
Optical Light Microscopy

The present study was performed on primary AlSi10MgMn cast alloy to analyze the morphology and composition of complex microstructure of the intermetallic phases. AlSi10MgMn cast alloy is a typical casting alloy used for parts with thin walls and complex geometry. It offers good strength, hardness and dynamic properties and is therefore also used for parts subject to high loading. In this study, several methods were used such as: optical light microscopy (LM) and scanning (SEM) electron microscopy in combination with EDX analysis using standard etched or deep etched sample to identify intermetallic. Alloy was analyzed in as-cast state (rapidly cooled right after casting) and after T6 heat treatment. T6 treatment (solution annealing, quenching and age hardening) improves mechanical properties. The results show that the microstructure of AlSi10MgMn alloy consisted of several phases: α-matrix, eutectic, Fe-rich intermetallic phases (Al15(FeMn)3Si2, Al5FeSi), Mg2Si, Al8FeMg3Si6 and of other phases in formation. Iron-rich intermetallic phases are well known to be strongly influential on mechanical properties in Al-Si alloys. The most common morphology was the long platelets of Al5FeSi phase. After heat treatment were observed spheroidisation of eutectic Si, dissolution and fragmentation of Fe-phases.

scholarly journals Effect of Ce Addition and Heat Treatment on Microstructure Evolution and Tensile Properties of Industrial A357 Cast Alloy

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1100
Author(s):  
Yanfeng Wang ◽  
Qian Liu ◽  
Zheng Yang ◽  
Changming Qiu ◽  
Kuan Tan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rare Earth ◽  
Tensile Properties ◽  
Cast Alloy ◽  
Fracture Pattern ◽  
Unmodified Alloy ◽  
Constitutional Undercooling ◽  
T6 Heat Treatment ◽  
Eutectic Si

The effects of adding different Ce contents (0–0.32 wt.%) on the microstructure, mechanical properties, and fracture morphology of industrial A357 cast alloy in as-cast and T6 heat treatment were studied. The main purpose of this study is to improve the microstructure stability and tensile properties of industrial A357 cast alloy. The microstructural analyses indicate that the addition of Ce causes refinement of the α-Al primary phase for the reason that the formation of intermetallic compounds containing (AlSiCeMg) elements enriches the front of the solid–liquid interface, which causes an increase in constitutional undercooling. Simultaneously, the addition of Ce also affected the characteristics of eutectic Si particles, which make its morphology change from acicular structures into fragmented and spheroidized. This is mainly due to the formation of Ce-rich precipitates during solidification, which increase the constitutional undercooling and suppress the nucleation of the eutectic Si particles, resulting in the change of eutectic Si characteristics. Moreover, the needle-like morphology of a Fe-containing intermetallic is transformed into α(AlSiFeCe) phase containing rare earth Ce when part of the Ce atoms entered β(Al5FeSi) phase compounds. The tensile properties of the modified alloys were improved in the as-cast and T6 heat treatment as a consequence of simultaneous refinement of both secondary dendrite arm spacing and grains and the improvement of eutectic Si particles and Fe-containing intermetallic morphology. The fracture surface of the modified alloy has more dimples than the unmodified alloy, which indicates that the main fracture pattern of the modified alloy is dimple fracture caused by the crack of eutectic Si particles. The optimal percentage of Ce in industrial A357 cast alloy was determined to be 0.16 wt.% according to the change of microstructures structure and mechanical properties. These experimental results provide a new basis for adding rare earth Ce to improve the performance of parts in the actual production of industrial A357 cast alloy.

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