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

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.

2015 ◽  
Vol 817 ◽  
pp. 127-131
Author(s):  
Yan Peng Pan ◽  
Zhi Feng Zhang ◽  
Bao Li ◽  
Bi Cheng Yang ◽  
Jun Xu

To develop Al-Si cast alloys with high performance is important for lightweighting vehicles. In this study, the effects of the alloying elements such as Si, Cu, Mg contents (5%-7% Si, 1%-3%Cu, 0.3%-0.9%Mg) on mechanical properties of a test Al-Si-Cu-Mg cast alloy was studied to achieve a specific composition. The experimental results show that the Al-6%Si-3%Cu-0.3%Mg alloy has better comprehensive mechanical properties after T6 heat treatment, which indicates a remarkable interaction of the alloying elements for improving performance.


2014 ◽  
Vol 782 ◽  
pp. 365-368
Author(s):  
Mária Chalupová ◽  
Eva Tillová ◽  
Mária Farkašová

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.


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.


2016 ◽  
Vol 850 ◽  
pp. 594-602 ◽  
Author(s):  
Cong Xu ◽  
Cheng Yuan Wang ◽  
Hai Jun Yang ◽  
Zhi Guo Liu ◽  
Hiroshi Yamagata ◽  
...  

The solidification behavior, microstructural evolution and mechanical properties of Al-Si-Mg foundry alloy with different Ti additions were investigated in the present study. The solidification behavior of those A357 alloys was analyzed through thermal analysis. The microstructures were examined by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed that the addition of Ti could refine grains of A357 as-cast alloy due to a good restriction on the grain growth, but Ti could not refine secondary dendrite arm spacing (SDAS), thus mechanical properties of the A357 as-cast alloy did not improved significantly. After T6 heat treatment, the microstructure with α-Al dendrites with the Al-Si eutectics at interdendritic space was replaced by a homogeneous α-Al matrix with a nonuniform dispersion of discrete, spheroidizing and coarse silicon particles. Hence, compared with the as-cast alloys, both of the strength and ductility of the T6 treated alloys are significantly improved, and an optimal combination of strength and elongation of the A357 alloy can be achieved by the 0.8 wt.% Ti addition after T6 heat treatment.


Alloy Digest ◽  
1953 ◽  
Vol 2 (10) ◽  

Abstract CONDULOY is a low beryllium-copper alloy containing about 1.5% nickel. It responds to age-hardening heat treatment for improved mechanical properties. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on casting, heat treating, machining, and joining. Filing Code: Cu-11. Producer or source: Brush Beryllium Company.


Alloy Digest ◽  
1985 ◽  
Vol 34 (5) ◽  

Abstract ALUMINUM 319.0 is a general-purpose foundry alloy that is moderately responsive to heat treatment. It has excellent casting characteristics and good mechanical properties. Among its many uses are crankcases, housings, engine parts, typewriter frames and rear-axle housings. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as creep and fatigue. It also includes information on low and high temperature performance as well as casting, heat treating, machining, and joining. Filing Code: Al-256. Producer or source: Various aluminum companies.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 647 ◽  
Author(s):  
Bingrong Zhang ◽  
Lingkun Zhang ◽  
Zhiming Wang ◽  
Anjiang Gao

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%.


2019 ◽  
Vol 38 (2019) ◽  
pp. 892-896 ◽  
Author(s):  
Süleyman Tekeli ◽  
Ijlal Simsek ◽  
Dogan Simsek ◽  
Dursun Ozyurek

AbstractIn this study, the effect of solid solution temperature on microstructure and mechanical properties of the AA7075 alloy after T6 heat treatment was investigated. Following solid solution at five different temperatures for 2 hours, the AA7075 alloy was quenched and then artificially aged at 120∘C for 24 hours. Hardness measurements, microstructure examinations (SEM+EDS, XRD) and tensile tests were carried out for the alloys. The results showed that the increased solid solution temperature led to formation of precipitates in the microstructures and thus caused higher hardness and tensile strength.


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