Influence of Solution Heat Treatment on Microstructures of Semisolid Cast 7075 Aluminium Alloy

2011 ◽  
Vol 339 ◽  
pp. 371-374 ◽  
Author(s):  
Narissara Mahathaninwong ◽  
Sirikul Wisutmethangoon ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Aluminium Alloy ◽  
Solution Heat Treatment ◽  
Treatment Time ◽  
Solution Treatment ◽  
Treated Sample ◽  
The Matrix ◽  
Semi Solid ◽  
Mgzn2 Phase

Influence of temperature and time of solution heat treatment on the microstructures of rheo-casting 7075 aluminium alloy produced by a novel technique, the Gas Induced Semi Solid (GISS) technique, had been investigated in this study. The microstructure of the as-cast specimens mainly consisted of matrix-α (Al) and grain boundary (GB)-eutectic phase (α-Al + Mg(Zn,Cu,Al)2). After solution heat treatment at 480 °C for 1 h, MgZn2 phase at the grain boundary was observed to have dissolved and coarse black particles of Mg2Si were observed to form in the matrix. In comparison, when solutionizing temperature of 450 °C was applied, it took 4 h of solution treatment time in order to dissolve the same portion of GB phase and MgZn2 phase, and coarse black particles of Mg2Si were found to form in the 8 h solution treated sample.

Effect of Heat-Treatment Time on Microstructure and Mechanical Properties of Mg-5Gd-2Y-2Zn-0.5Zr Alloy

2012 ◽  
Vol 482-484 ◽  
pp. 1384-1389 ◽  
Author(s):  
Ling Gang Meng ◽  
Can Feng Fang ◽  
Peng Peng ◽  
Nai Pu Li ◽  
Qiong Zhu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Treatment Time ◽  
Time Range ◽  
Lpso Phase ◽  
High Temperature Heat Treatment ◽  
Lpso Structure ◽  
The Matrix ◽  
New Type ◽  
The Stability

Microstructure evolution of Mg-5Gd-2Y-2Zn-0.5Zr alloy during high temperature heat-treatment at 500°C in the time range 10-70h was investigated. The results show that after adding the element Y, the as-cast Mg-5Gd-2Y-2Zn-0.5Zr alloy forms the Mg12Zn(Y,Gd) phase with 18R-LPSO structure at the grain boundary. During heat-treatment at 500°C, the stability of 18R-LPSO structure is weakened by Gd atoms, parts of LPSO phases dissolve gradually into the matrix with time prolonged and a new type Mg(Y,Gd)Zn phase come into being. LPSO phase in the grain boundary can ensure the ultimate tensile strength and elongation of the alloy, and effect of dissevering on the LPSO phase by Mg(Gd,Y)Zn phase results the decrease of UTS and elongation.

Effect of the Two-Step Solution Heat Treatment on the Microstructure of Semisolid Cast 7075 Aluminum Alloy

2012 ◽  
Vol 488-489 ◽  
pp. 243-247 ◽  
Author(s):  
Saowalak Kongiang ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin ◽  
Sirikul Wisutmethangoon
Keyword(s):  
Heat Treatment ◽  
Treatment Condition ◽  
Solution Heat Treatment ◽  
Solution Treatment ◽  
Heat Treatment Condition ◽  
Single Step ◽  
Eutectic Phase ◽  
Solution Treated ◽  
The Matrix ◽  
Black Particle

Effect of the two-step solution heat treatment on the microstructure of semisolid cast 7075 aluminium alloy has been studied. The microstructure of the as-cast specimens mainly consisted of matrix-α (Al) and grain boundary (GB)-eutectic phase (α-Al + Mg(Zn,Cu,Al)2). After solution treating, coarse black particles were found to form in the single-step solution treated specimens at the condition of 450 °C for 8 h and 480 °C for 1 h, respectively. Two-step solution heat treatment resulted in the reduction of coarse black particle formation while maintaining the same amount of eutectic MgZn2phase dissolution as the high temperature single-step solution treatment. Therefore, the two-step solution heat treatment enables alloying elements dissolved into the matrix without overheating and hence decreases coarse black particles. The optimum two-step solution heat treatment condition derived from this study was 400 °C for 8 h + 450 °C for 4 h.

Solution Heat Treatment of 7075 Aluminum Alloy Affected on Anodic Oxide Layer

2016 ◽  
Vol 867 ◽  
pp. 19-23 ◽  
Author(s):  
Itsaree Iewkitthayakorn ◽  
Somjai Janudom ◽  
Narissara Mahathaninwong
Keyword(s):  
Heat Treatment ◽  
Oxide Film ◽  
Solution Heat Treatment ◽  
Treatment Time ◽  
Solution Treatment ◽  
Secondary Phase ◽  
Anodic Oxide ◽  
Al Alloy ◽  
Heat Treated

This research focused on the effect of solution heat treated microstructures on anodic oxide formations of casting 7075 Al alloy. The casting specimens were solution heat treated at 450°C for various holding. The results showed that the quality of anodic oxide film on the specimen with 4h solution heat treatment time was higher than that of at other conditions. Because its microstructures obtained the lowest amounts of secondary phase particles leading to improve the quality of oxide film and also reduce defects in oxide film. On the other hand, coarse black particles of Mg2Si formed increasingly in microstructures of specimens after solution treatment at prolong holding time of 8h and 16h resulted in discontinues oxide films forming on them.

scholarly journals Selection of optimal solution heat treatment of the casting cylinder heads

2018 ◽  
Vol 157 ◽  
pp. 02053 ◽  
Author(s):  
Eva Tillová ◽  
Mária Chalupová ◽  
Lenka Kuchariková ◽  
Juraj Belan ◽  
Denisa Závodská
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Treatment Time ◽  
Crack Nucleation ◽  
Particle Density ◽  
Solution Treatment ◽  
Optimal Solution ◽  
Solution Temperature ◽  
Selection Of

The effect of solution treatment on mechanical properties (UTS, elongation, Brinell hardness) and microstructure (Si-morphology and Si-size) of an aluminium alloy (A356) used for casting cylinder heads was studied. The tests were carried out with specimens machined from the bulkheads of V8 engine blocks cast by the low pressure process. The samples were tested in as-cast and T6 heat treating conditions (solution heat treatment at 530°C with different time - 2, 3, 4, 5, 6, 7 hours, quenching in water at 20°C and precipitation hardened for 4 hour at 160°C). The results show that used heat treatment improves mechanical properties of the cylinder head casts. Tensile strength and hardness of specimens increase with solution treatment time. The hardness is a reflection of solution strengthening and silicon particle distribution in matrix. Solution temperature 530°C and 5 hours solution time is appropriate to obtain better morphology and distribution of Si particles in microstructure. Prolonged solution treatment (more than 5 hours) leads to a coarsening of the Si particles, while the numerical Si density decreases. As the particle density decreases, a fewer number of sites are available for crack nucleation, and hence, the fracture properties are improved. The data obtained from this study will be used to improve process control, and to help the selection of heat treatment of the casting for future products.

Effect of Short Solution Heat Treatment Time on the Microstructure and Properties of Al-Si-Mg-Cu Alloys

2021 ◽  
Vol 58 (12) ◽  
pp. 763-780
Author(s):  
P. Zhuang ◽  
H. Shi ◽  
Z. Zhang ◽  
R. Chai ◽  
J. Zan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Treatment Time ◽  
Eutectic Silicon ◽  
Dendritic Structure ◽  
Casting Alloy ◽  
Cu Alloys ◽  
Intermetallic Precipitates ◽  
The Matrix ◽  
Silicon Particles

Abstract In this work, a solution heat treatment of Al-Si-Mg-Cu casting alloy was analyzed. A new short solution heat treatment (SHT) with only 60 min has been allowed. The results revealed that this short SHT enables the improvement of the dendritic structure and the spheroidization of the eutectic silicon particles. Furthermore, the alloy showed improved mechanical properties when compared to the same alloy subjected to a longer SHT of 4 h. It was observed that increasing the SHT temperature can accelerate the dissolution and homogenization of the silicon particles and intermetallic precipitates in the matrix.

Microstructure Evolution during Solution Heat Treatment of Semisolid Cast 2024 Aluminum Alloy

2011 ◽  
Vol 339 ◽  
pp. 714-717 ◽  
Author(s):  
Siriwan Pannaray ◽  
Sirikul Wisutmethangoon ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Solution Heat Treatment ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Grain Structure ◽  
Al Alloy ◽  
Solution Treatment Temperature ◽  
2024 Aluminum Alloy ◽  
Semi Solid

The aim of this study is to determine the appropriate solution treatment temperature and time of semi solid 2024 Al alloy. Solution heat treatment at 450°C and 480 °C for various times, from 4 hours to 16 hrs, were applied followed by artificial aging at 220 °C for 1 hr. Microstructure of the semi solid cast 2024 aluminum alloy mainly showed globular grain structure which consisted of matrix-α (Al) and grain boundary (GB) - eutectic phases (α+Al2CuMg/Al2Cu). Eutectic GB phases was found to completely dissolved after solution heat treatment at 480°C for 14 hrs while sample solution treated at 450°C for the same time showed the existence of remaining GB phases. Prolonging heat treatment after 14 hrs at both temperatures resulted in the formation of coarse black particles at the grain boundaries which were identified as Mg2Si phases. Therefore the suitable solution treatment of the alloy in this study was at 480°C for 14 hrs.

Research on Microstructure and Mechanical Properties Evolution of Rheocast and Thixocast 319s Aluminum Alloy

2016 ◽  
Vol 850 ◽  
pp. 802-808 ◽  
Author(s):  
Kang Du ◽  
Xiao Kang Liang ◽  
Da Quan Li ◽  
Qiang Zhu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Time ◽  
Eutectic Silicon ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solid Alloy ◽  
Obvious Effect ◽  
Higher Temperature ◽  
Semi Solid

In semi-solid rheocast and thixocast industry, T6 heat treatment was one key factor to improve the mechanical properties of the castings. The microstructure evolution was closely influenced by heat treatment temperature and time. In this paper, the morphology change of eutectic silicon in semi-solid alloy during different heat treatment time was firstly observed. The changes of both roundness and aspect show that the silicon particles underwent fragmentation, coarsening and growing up processes during solution treatment. Then, the mechanical properties after stand T6 and T6 with higher temperature were compared. It may be concluded that the higher temperature doesn’t have obvious effect to increase the mechanical strength, but severe negative effect on the elongation. Finally, the incipient melting defect appeared in higher temperature T6 was proved and its relationship with elongation was analysed.

TEM Investigations of Electron 21 Magnesium Alloy

2007 ◽  
Vol 130 ◽  
pp. 175-180 ◽  
Author(s):  
Andrzej Kiełbus
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Solution Heat Treatment ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Air Cooling ◽  
Transmission Electron ◽  
The Matrix ◽  
Cast Condition ◽  
Cast Microstructure

The paper presents results of TEM investigations of Elektron 21 magnesium alloy in as cast condition and after heat treatment. The compositions of the Elektron 21 alloy used in the present study was Mg-2,7%wtNd-1,2%wtGd-0,47%wtZr. Solution heat treatment was performed at 520°C/8 h/water. Ageing treatments were performed at 200°C/4÷96h and 300°C/48h with cooling in air. The as-cast microstructure and microstructural evolution during heat treatment were examined by transmission electron microscopy. Samples were prepared using Gatan PIPS ion mill. Examinations were performed in a JEM 2010 ARP microscope. The microstructure of the cast alloy consists of a-Mg phase matrix with precipitates of Mg12(Ndx,Gd1-x) phase at grain boundaries. After solution treatment the Mg12(Ndx,Gd1-x) phase dissolved in the matrix. The ageing treatment applied after solution treatment with air-cooling caused precipitation of a β’ and β phases.

Optimization of Heat Treatment Process on Vacuum Die-Casting AT72 Magnesium Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 307-312
Author(s):  
Da Quan Li ◽  
Yong Liu ◽  
Jun Xu ◽  
Shuang Shao ◽  
Chun Shui Xu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Grain Boundary ◽  
Treatment Process ◽  
Die Casting ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Heat Treatment Process ◽  
Vacuum Die Casting ◽  
The Matrix

The effect of heat treatment on vacuum die-casting (VDC) AT72 magnesium alloy was studied. The optimal process of heat treatment was obtained. The result shows that the alloy was composed of α-Mg, Mg17Al12and Mg2Sn. After solution treatment at 686K for 24h, Mg17Al12completely dissolved in α-Mg matrix. With the aging treatment following solution treatment, Mg17Al12kept precipitating in the matrix and along grain boundary. Moreover, Mg2Sn distributed along the grain boundary did not disappear after solution treatment at 686K. This indicates that Mg2Sn phase exhibits very high thermal stability. The heat treatment process was optimized with solution at 686K for 24h plus ageing at 473K for 18h, in the condition of which AT72 magnesium alloy exhibits a maximum hardness with value of 90.8Hv. The successful application of heat treatment for AT72 magnesium alloy could be attributed to the elimination of the air bubble in the casing through VDC. However, the porosity in the cast couldnt be efficiently eliminated by VDC, which result in the growth of shrinkage pore.

Effect of Solution Heat Treatment and Additives on the Microstructure of Al – Si (A413.1) Automotive Alloys

2004 ◽  
Vol 467-470 ◽  
pp. 399-406 ◽  
Author(s):  
M.A. Moustafa ◽  
F.H. Samuel ◽  
H.W. Doty
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Treatment Time ◽  
Microstructural Analysis ◽  
Solution Treatment ◽  
Microstructural Characteristics ◽  
Unmodified Alloy ◽  
Heat Treated ◽  
Cast Condition

A study was carried out to determine the role of additives such as Mg and Cu on the microstructural characteristics of grain refined, Sr-modified eutectic A413.1 alloy (Al-11.7% Si) during solution heat treatment. For comparison purposes, some of the alloys were also studied in the non-modified condition. The alloys were cast in a steel permanent mold preheated at 425 °C that provided a microstructure with an average dendrite arm spacing (DAS) of ~ 22 µm. Castings were solution heat treated at 500 ± 2 °C for time up 24 h, followed by quenching in warm water (at 60 °C). Microstructural analysis of the as-cast and heat-treated castings was carried out using optical microscopy in conjunction with image analysis. Phase identifications were done using the electron probe microanalysis (EPMA) technique. In the as-cast condition, the addition of 0.42 wt% Mg to the unmodified alloy produced relatively large Si particles compared to the base A413.1 alloy. The Si particle size remained more or less the same with increase in solution treatment time and Mg level. Both Mg2Si and Al2Cu phases were observed to dissolve almost completely after 8 h solution time, while the Al5Cu2Mg8Si6 phase was found to persist even after 24 h.

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