Effect of Heat Treatment on the Microstructure of Gravity Cast and Squeeze Cast Al-Si-Mg Alloy

2015 ◽  
Vol 830-831 ◽  
pp. 164-167
Author(s):  
Arjun Bala Krishnan ◽  
Kavin Selvaraj ◽  
Akhil Madhusoodhanan Geethakumari ◽  
Ravi Manickam
Keyword(s):  
Heat Treatment ◽  
Squeeze Casting ◽  
Cast Alloy ◽  
Eutectic Silicon ◽  
Solution Treatment ◽  
A356 Alloy ◽  
Sand Cast ◽  
Squeeze Cast ◽  
Cast Alloys ◽  
Gravity Cast

The present work deals with the effect of solutionising heat treatment on the features of Al-7Si-0.3Mg (A356) alloy in terms of microstructural modifications and hardness. The microstructure of sand cast and gravity cast alloys are coarse which results in lower strength compared to the alloys cast using modern casting techniques such as squeeze casting which is used for the fabrication of near-net-shaped castings. The influence of enhanced cooling rate on the hardness and microstructure of the squeeze casting technique has been exploited in the present study. In order to optimise the heat treatment process, the microstructure of the gravity and squeeze cast alloys were compared after solution treatment. The quantitative analysis of the microstructure was carried out using an image analyser attached to the optical microscope. The aspect ratio, particle count and circularity of eutectic silicon and SDAS are measured. The squeeze cast alloy is found to have finer microstructure with enhanced properties compared to the gravity cast alloy.

Effect of Aging on Characterization of Sr-Modified Stir Cast A356/Al2O3 Composite

2017 ◽  
Vol 753 ◽  
pp. 33-38 ◽  
Author(s):  
Anne Zulfia Syahrial ◽  
Ahadya Pancasakti
Keyword(s):  
Heat Treatment ◽  
Eutectic Silicon ◽  
Solution Treatment ◽  
A356 Alloy ◽  
Casting Process ◽  
Stir Casting ◽  
Technical Condition ◽  
Micro Particles ◽  
Fe Intermetallics ◽  
Light Material

A356/Al2O3 composites with Sr modifier were produced by stir casting process. The composites were further heat treated to obtain light material with superior characteristics through precipitation hardening of Mg2Si precipitate. The A356 alloy is reinforced with 10 %Vf Al2O3 micro particles. Small amount of Sr is added to modify eutectic silicon morphology from plate-like into fibrous. The composites were prepared by stir casting method in order to obtain dispersed reinforcement particulates within the matrix. T6 heat treatment is employed to the fabricated composites for 2, 4, 6, 8, and 10 hours of aging time to improve the properties. The result reveals that an optimum values of tensile strength, impact strength, hardness and wear rate are achieved by conducting 6 hours of aging. Longer than that, the properties will decline as a result of incoherent phase domination. Small amount of Sr is shown to be able to change the morphology of eutectic silicon from plate-like into fibrous. However, Fe-intermetallics formation, porosity, and negative effect from solution treatment due to improper technical condition during heat treatment are found to contribute on deterioration of mechanical properties of the material.

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.

scholarly journals Investigation of the Effect of Heat Treatment on the Microstructures and Mechanical Properties of Al-13Si-5Cu-2Ni Alloy

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 688
Author(s):  
Zhi-Fa Wang ◽  
Tian-Jing Miao ◽  
Shu-Qing Kou ◽  
Shuang Zhang ◽  
Feng Qiu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Cast Alloy ◽  
Eutectic Silicon ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Solution Treatment Temperature ◽  
Solid Solution Treatment ◽  
Microstructures And Mechanical Properties

An experimental investigation was carried out to study the effects of solid solution treatment and aging treatment on the microstructures and mechanical properties of an Al-13Si-5Cu-2Ni alloy. The results show that the size of eutectic silicon decreased with solid solution treatment temperature increasing until 510 °C. Subsequently, the eutectic silicon size continued to increase as the temperature increased to 520 °C. Initially, the acicular eutectic silicon of the as-cast alloy was 10.1 μm in size. After the solid solution treatment at 510 °C, the eutectic silicon size was reduced to 6.5 μm. The θ′ phase is the main strengthening phase in the alloy, therefore, the effect of aging treatment on θ′ phases was explored. As the aging time increased, the diameter, length, and fraction volume of the θ′ phases were found to increase. The main reason for the improved performance of this alloy following heat treatment is the passivation spheroidization of the silicon phase and Orowan strengthening due to the θ′ phases. The optimal tensile strength of an Al-13Si-5Cu-2Ni alloy was obtained after solid solution treatment at 510 °C for 8 h followed by an aging treatment at 165 °C for 8 h. Therefore, this work has great significance for promoting the application of Al alloys at high temperatures.

Effect of Mg and Cu Additions on Microstructure and Mechanical Properties of Squeeze Casting Al-Si-Cu-Mg Alloy

2016 ◽  
Vol 850 ◽  
pp. 511-518 ◽  
Author(s):  
Hai Jun Liu ◽  
Lie Jun Li ◽  
Jian Wei Niu ◽  
Ji Xiang Gao ◽  
Chuan Dong Ren
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Artificial Aging ◽  
Squeeze Casting ◽  
Solution Treatment ◽  
Mg Alloys ◽  
Percentage Elongation ◽  
Microstructure And Mechanical Properties ◽  
Content Ratio ◽  
Cast Alloys

The effects of Mg and Cu additions with different contents on the mechanical properties of Al-Si alloy prepared by indirect squeeze casting have been experimentally investigated. The microstructure and mechanical properties of as-cast and T6-treated Al-Si-Cu-Mg alloys were tested by OM, SEM, DSC and tensile measurement, where the samples were produced by artificial aging at 180°C for 8 h after solution treatment at 540°C for 4 h. It has been found that for the as-cast alloys, with increasing contents of Mg and Cu the tensile strength (UTS) and yield strength (YS) increased, while the percentage elongation (El) decreased. And the optimal mechanical properties of Al-Si-Cu-Mg alloys were obtained under the content ratio of Cu/Mg within 4, where the UTS and El reached 426 MPa and 6.3% after T6 treated, respectively.

Ultrasonic Rheocasting for Refinement of Mg Alloys Reinforced with LPSO Phase

2018 ◽  
Vol 941 ◽  
pp. 1607-1612 ◽  
Author(s):  
Shu Lin Lü ◽  
Xiong Yang ◽  
Liang Yan Hao ◽  
Shu Sen Wu
Keyword(s):  
Mechanical Properties ◽  
Squeeze Casting ◽  
Mg Alloys ◽  
Average Thickness ◽  
Squeeze Pressure ◽  
Lpso Phase ◽  
Long Period ◽  
Lpso Structure ◽  
Cast Alloys ◽  
Gravity Cast

In this work, ultrasonic rheocasting was used to refine the microstructures of Mg alloys reinforced with long period stacking ordered (LPSO) phase. The semisolid slurries of Mg-Zn-Y and Mg-Ni-Y alloys were prepared by ultrasonic vibration (UV) and then formed by rheo-squeeze casting under high squeeze pressure (~ 400 MPa). The effects of UV and squeeze pressure on microstructure and mechanical properties of the Mg alloys were studied. The results reveal that UV and rheo-squeeze casting can significantly refine the LPSO structure and alpha-Mg matrix in Mg alloys, but they cannot change the phase compositions of the alloys or the type of LPSO phase. When the squeeze pressure is 400 MPa, the average thickness of LPSO phase is decreased, and the block LPSO structure is completed eliminated and uniformly distributed at the grain boundaries. Compared with the gravity cast alloys without UV, mechanical properties of the rheocast Mg alloys were enhanced and reached the maximums when the squeeze pressure was 400 MPa.

Mechanical Properties of A356 Aluminum Cast Alloy Shaped by Permanent Mold Casting

2014 ◽  
Vol 941-944 ◽  
pp. 89-92
Author(s):  
Ping Chen ◽  
Jian Min Zeng ◽  
Wu Kui Gan ◽  
Jin Bo Liu
Keyword(s):  
Mechanical Properties ◽  
Cast Alloy ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Permanent Mold ◽  
Permanent Mold Casting ◽  
Mold Casting ◽  
Needle Morphology ◽  
A356 Aluminum ◽  
Alloy Cast

A356 is a heat treatable cast alloy which has been widely applied in aviation and automobile industries. In this paper a Sb modified A356 alloy cast with permanent mold has been investigated in order to improve its mechanical properties by changing the needle morphology of the eutectic silicon. The results show that a small amount of Sb addition can contribute refined eutectic silicon morphology and enhance the mechanical properties, especially elongation of the A356 cast alloy poured in permanent molds. The optimal addition of Sb is 0.2 wt.%.

Study of Artificial Aging Temperature Effect on Morphology of Structural Parameters in Aluminium Cast Alloy

2017 ◽  
Vol 891 ◽  
pp. 354-359
Author(s):  
Lenka Kuchariková ◽  
Eva Tillová ◽  
Mária Chalupová ◽  
Juraj Belan ◽  
Ivana Švecová ◽  
...  
Keyword(s):  
Artificial Aging ◽  
Cast Alloy ◽  
Structural Parameters ◽  
Eutectic Silicon ◽  
Solution Treatment ◽  
Analytical Techniques ◽  
Intermetallic Phases ◽  
Holding Time ◽  
Different Temperatures ◽  
Alloy Microstructure

The contribution describes changes in morphology of structural parameters in recycled (secondary) AlSi9Cu3 cast alloy microstructure. These changes depended on different temperatures of artificial aging. The T6 heat treatment, which was used for affecting the structural parameters morphology, consisted of solution treatment at temperature 515 °C with holding time 4 hours, water quenching at 40°C and artificial aging at different temperatures 130 °C, 150 °C, 170 °C, 190 °C and 210 °C with different holding time 2, 4, 8, 16 and 32 hours. The morphology of structural parameters was observed using combination of different analytical techniques (light microscopy upon black-white and colour etching, scanning electron microscopy - SEM upon deep etching). The different temperatures of artificial aging led to changes in microstructure include the spheroidization and coarsening of eutectic silicon, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases, the dissolution of precipitates and the precipitation of finer hardening phase (Al2Cu).

Tensile Properties of Squeeze Cast Mg-Al-Sr Alloy under Applied Pressures

2015 ◽  
Vol 1088 ◽  
pp. 181-185
Author(s):  
Li Fang ◽  
Henry Hu ◽  
Shu Ping Wang
Keyword(s):  
Tensile Properties ◽  
Squeeze Casting ◽  
Cast Alloy ◽  
Microstructural Analysis ◽  
Applied Pressure ◽  
External Pressure ◽  
Squeeze Cast ◽  
Porosity Reduction ◽  
Alloy Increase ◽  
Porosity Measurements

The focus of this study is on development of alternative manufacturing processes for potential high temperature magnesium-aluminium-strontium alloys. The effect of external pressure on tensile properties of squeeze cast Mg-Al-Sr alloy was investigated. Four different applied levels, 0, 30, 60 and 90 MPa, were employed to exert on a Mg-6 wt.% Al – 0.5 wt.% Sr alloy during squeeze casting. The results of tensile testing indicate that the ultimate tensile strength (UTS), yield strength (YS) and elongation (Ef) of the squeeze cast Mg-Al-Sr alloy increase with increasing applied pressure level. The microstructural analysis and porosity measurements suggest that the tensile property enhancement resulting from applied pressure should be attributed to microstructure refinement and porosity reduction of the squeeze cast alloy.

Identification and Analysis of Intermetallic Phases in Age-Hardened Recycled AISi9Cu3 Cast Alloy

2012 ◽  
Vol 59 (4) ◽  
pp. 385-396 ◽  
Author(s):  
Lenka Hurtalová ◽  
Eva Tillová ◽  
Mária Chalupová
Keyword(s):  
Tensile Strength ◽  
Automotive Industry ◽  
Cast Alloy ◽  
Eutectic Silicon ◽  
Solution Treatment ◽  
Analytical Techniques ◽  
Intermetallic Phases ◽  
Holding Time ◽  
Age Hardening ◽  
Image Analyzer

PurposeThe influence of age-hardening solution treatment at temperature 515_C with holding time 4 hours, water quenching at 40_C and artificial aging by different temperature 130_C, 150_C, 170_C and 210_C with different holding time 2, 4, 8, 16 and 32 hours on changes in morphology of Fe-rich Al15(FeMn)3Si2 and Cu-rich (Al2Cu, Al-Al2Cu-Si) intermetallic phases in recycled AlSi9Cu3 cast alloy. Material/Methods: Recycled (secondary) AlSi9Cu3 cast alloy is used especially in automotive industry (dynamic exposed cast, engine parts, cylinder heads, pistons and so on). Microstructure was observed using a combination of different analytical techniques (scanning electron microscopy upon standard and deep etching and energy dispersive X-ray analysis - EDX) which have been used for the identification of the various phases. Quantitative study of changes in morphology of phases was carried out using Image Analyzer software NIS-Elements. The mechanical properties (Brinell hardness and tensile strength) were measured in line with STN EN ISO. Results/Conclusion: Age-hardening led to changes in microstructure include the spheroidization of eutectic silicon, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases and Al-Al2Cu-Si phases were fragmented, dissolved and redistributed within _-matrix. These changes led to increase in the hardness and tensile strength in the alloy.

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