EFFECT OF HEAT TREATMENTS ON THE MICROSTRUCTURE AND PROPERTIES OF Al/SiCp COMPOSITES PREPARED BY NON-ASSISTED INFILTRATION

2012 ◽  
Vol 1373 ◽  
Author(s):  
R. Martínez-López ◽  
M. I. Pech-Canul ◽  
Z. Chaudhury ◽  
L. A. González
Keyword(s):  
Heat Treatment ◽  
Thermal Stresses ◽  
Solution Treatment ◽  
Heat Treatments ◽  
Peak Hardness ◽  
Maximum Hardness ◽  
X Ray ◽  
Solution Treated ◽  
Hardness Tests ◽  
Heat Treated

ABSTRACTAl/SiCp composites fabricated by the non-assisted infiltration route are attractive materials for various engineering applications. However, the presence of thermal stresses can impair their mechanical properties if they are utilized directly after processing. Therefore, heat treatments are potential solutions to this problem. In this work, the effect of T6-heat-treatment on the microstructure and hardness of Al/50% SiCp composites prepared by the non-assisted infiltration route is investigated. Previous to preform preparation, the SiC powders are coated with colloidal SiO2. Infiltration tests are conducted using two experimental Al-Si-Mg alloys. The composites are sectioned in specimen sizes of 1 cm2 and prepared using standard metallographic procedures. Then they are heat treated performing a solution treatment at 350°C for 3 h and artificial aging at 170°C for 1, 3 and 5 hours. In addition, the specimens are characterized by X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). They are also characterized in hardness tests, comparing the behavior for the alloy with and without the various treatments. The results show that heat treatments do not affect the matrix/reinforcement interfacial condition and that the undesirable Al4C3 phase is not developed as consequence of thermal treatments. Hardness tests show that for alloy 1 the maximum hardness value is for the solution-heat-treated samples at 350°C and 5 h aging (28.26±4.02 HC); for alloy 2 the maximum hardness is achieved with solution heat treatment at 350°C and 3 h aging (25.86±4.05 HC). For composites processed with alloy1, the maximum hardness is obtained for the solution treated sample at 350 ° C for 3 h (91.8±2.17 HC), whereas for composites processed with alloy 2 the peak hardness is obtained in solution treated samples and aged at 170°C for 1 h (95.2±0.94 HC).

An investigation on microstructure and mechanical properties of post-weld heat-treated friction stir welds in aluminum alloy 2024-W

2012 ◽  
Vol 227 (4) ◽  
pp. 649-662 ◽  
Author(s):  
Hakan Aydın ◽  
Ali Bayram ◽  
İsmail Durgun
Keyword(s):  
Room Temperature ◽  
Welded Joint ◽  
Solution Treatment ◽  
Heat Treatments ◽  
Maximum Hardness ◽  
Friction Stir ◽  
Base Materials ◽  
Heat Treated ◽  
Aluminum Alloy 2024 ◽  
Weld Heat

The present work describes the results obtained from microstructural and mechanical evaluation of post-weld heat treated friction stir welds of 2024 aluminum alloys in the W temper state. Post-weld heat treatments have been carried out at 510 °C for 2.5 h followed by ageing at room temperature for 6 months, at 100 °C and 190 °C for 10 h, and by cooling in static air (O-temper). The solution treatment caused abnormal coarsening of the grains in the stir zone, which resulted in a drop in microhardness. The strength of the as-welded joint was significantly incrased by post weld heat treatments. The maximum hardness and strength values were obtained in T6 (190 °C, 10 h) treated joint. However, the T6 (190 °C, 10 h) treated joint had the lowest ductility. On the other hand, the tensile properties of the post-weld heat treated joints were far lower than those of the unwelded base materials in the same temper states. In addition, the post-weld heat treatments did not significantly change the fracture locations of the friction stir welds.

scholarly journals Short Heat Treatments for the F357 Aluminum Alloy Processed by Laser Powder Bed Fusion

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6157
Author(s):  
Matteo Vanzetti ◽  
Enrico Virgillito ◽  
Alberta Aversa ◽  
Diego Manfredi ◽  
Federica Bondioli ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Precipitation Hardening ◽  
Solution Treatment ◽  
Heat Treatments ◽  
Point Of View ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Heat Treated ◽  
Direct Aging

Conventionally processed precipitation hardening aluminum alloys are generally treated with T6 heat treatments which are time-consuming and generally optimized for conventionally processed microstructures. Alternatively, parts produced by laser powder bed fusion (L-PBF) are characterized by unique microstructures made of very fine and metastable phases. These peculiar features require specifically optimized heat treatments. This work evaluates the effects of a short T6 heat treatment on L-PBF AlSi7Mg samples. The samples underwent a solution step of 15 min at 540 °C followed by water quenching and subsequently by an artificial aging at 170 °C for 2–8 h. The heat treated samples were characterized from a microstructural and mechanical point of view and compared with both as-built and direct aging (DA) treated samples. The results show that a 15 min solution treatment at 540 °C allows the dissolution of the very fine phases obtained during the L-PBF process; the subsequent heat treatment at 170 °C for 6 h makes it possible to obtain slightly lower tensile properties compared to those of the standard T6. With respect to the DA samples, higher elongation was achieved. These results show that this heat treatment can be of great benefit for the industry.

Effects of Heat Treatment on a High-Pressure Die-Cast Mg-La-Y Alloy

2011 ◽  
Vol 690 ◽  
pp. 210-213 ◽  
Author(s):  
Serge Gavras ◽  
Su Ming Zhu ◽  
Mark A. Easton ◽  
Mark A. Gibson ◽  
Jian Feng Nie
Keyword(s):  
Heat Treatment ◽  
High Pressure ◽  
Creep Resistance ◽  
Solution Treatment ◽  
Dislocation Motion ◽  
Heat Treatments ◽  
Dimensional Changes ◽  
Heat Treated ◽  
Die Cast ◽  
Solute Atoms

In this study effects of heat treatments on the creep resistance at 177°C/90MPa of a high-pressure die-cast Mg-2.70La-1.50Y (wt.%) alloy were examined. It was found that ageing at 160°C for 24 h (T5) or a solution treatment at 520°C for 1 h (T4) improved creep resistance and caused no blistering on the surface or dimensional changes to the die-cast specimens. TEM was used to characterize the microstructures of heat-treated samples. Improvements to creep resistance might be attributed to the pinning or otherwise retarding of dislocation motion by precipitates and/or solute atoms during creep.

Two-Step Aging Behaviour of Solution Treated A356 System Alloy

2018 ◽  
Vol 941 ◽  
pp. 1083-1087
Author(s):  
Masahiko Iijima ◽  
Tomoya Ozasa ◽  
Susumu Ikeno ◽  
Kenji Matsuda ◽  
Seiji Saikawa
Keyword(s):  
Solution Treatment ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Mg Alloy ◽  
Peak Hardness ◽  
System Alloy ◽  
Solution Treated ◽  
Heat Treated ◽  
Final Aging ◽  
Positive Effect

Al-7mass%Si-0.3mass%Mg alloy is widely applied to the automotive components, such as road wheel or suspension frame because of having higher ductility and corrosion resistance. Two-step aging behavior of solution treated Al-7mass%Si-0.3mass%Mg system alloy A356 cast into permanent mold and solution treated was investigated by micro-vickers hardness measurement, optical microscopy (OM) and transmission electron microscopy (TEM). The microstructure of as-cast state was consist of primary crystallized α-Al and secondary crystallized eutectic phases. Al-7mass%Si-0.3mass%Mg alloy after casting, the test specimens were heat treated for different pre-aging temperatures at 273K, 348K and 423K for various times after solution treatment at 813K for 36ks. After pre-aging treatment, the test specimens were heat treated for artificial aging at 523K for various times. The peak hardness increased almost the same value when the pre-aging temperature was 273K. On the other hands, positive effect of the final-aging was occurred after pre-aging at 348K and 423K with significantly increasing hardness in the under-aging region. The fine precipitates were observed in the specimen which was final aging at 523K after pre-aging at 348K and 423K.Such a positive effect is considered due to the influence of precipitated phase mainly such as clusters and /or G.P.zone.The present study aims to investigate the effect of pre-aged temperature on final-aged behavior in A356 system alloy.

Effect of Thermo-Mechanical Treatment (TMT) on Hardness of Heat-Treated Al-Mg-Si (6082) Alloys: Experimental Correlation Using (DOE) Method

2013 ◽  
Vol 376 ◽  
pp. 163-172 ◽  
Author(s):  
Mahmoud M. Tash ◽  
S. Alkahtani
Keyword(s):  
Heat Treatment ◽  
Aging Time ◽  
Solution Heat Treatment ◽  
Mechanical Treatment ◽  
Cold Work ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Solution Treated ◽  
Heat Treated ◽  
Thermo Mechanical Treatment

The present study was undertaken to investigate the effect of Thermo-mechanical Treatment (TMT) on aging and hardness of Al-Mg-Si (6082) alloys. The effect of cold work after solution treatment, aging time and temperature on the microstructure and hardness were studied. Hardness measurements were carried out on specimens prepared from 6082 alloys in the as solution treated specimens and heat-treated conditions, using different cold work percentage before aging treatment. Aging treatments were carried out for the as solution treated specimens (after quenching in water) as well as for the as cold worked specimens (after solution treatment and quenching in water). The specimens were aged at different conditions; Natural aging was carried out at room temperature for different periods of time. Artificial aging was performed at 100 °C, 150 °C, and 200 °C for various times. It is noticed that cold work, following solution treatment, accelerates the precipitation rate leading to a rise in strength.A statistical design of experiments (DOE) approach using fractional factorial design was applied to determine the influence of controlling variables of cold work and heat treatment parameters and any interactions between them on the hardness of 6082 alloys. A mathematical model is developed to relate the alloy hardness with the different metallurgical parameters i.e. Cold work prior solution heat treatment (CWBSHT), Cold work after solution heat treatment (CWASHT), Pre-aging Temperature (PA T0C), Pre-aging time (PA t h), Aging temperature (AT0C), Aging time (At h), Cold work after aging treatment (CWAAT), Annealing temperature (An.T0C) and Annealing time (An.t min) to acquire an understanding of the effects of these variables and their interactions on the hardness of Al-Mg-Si 6082 alloys.

scholarly journals Fabrication of TiO2Crystalline Coatings by Combining Ti-6Al-4V Anodic Oxidation and Heat Treatments

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
María Laura Vera ◽  
Mario Roberto Rosenberger ◽  
Carlos Enrique Schvezov ◽  
Alicia Esther Ares
Keyword(s):  
Heat Treatment ◽  
Anodic Oxidation ◽  
Heat Treatments ◽  
The Other ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray ◽  
Heat Treated ◽  
Natural Oxide ◽  
Scanning Electron

The bio- and hemocompatibility of titanium alloys are due to the formation of a TiO2layer. This natural oxide may have fissures which are detrimental to its properties. Anodic oxidation is used to obtain thicker films. By means of this technique, at low voltages oxidation, amorphous and low roughness coatings are obtained, while, above a certain voltage, crystalline and porous coatings are obtained. According to the literature, the crystalline phases of TiO2, anatase, and rutile would present greater biocompatibility than the amorphous phase. On the other hand, for hemocompatible applications, smooth and homogeneous surfaces are required. One way to obtain crystalline and homogeneous coatings is by heat treatments after anodic oxidation. The aim of this study is to evaluate the influence of heat treatments on the thickness, morphology, and crystalline structure of the TiO2anodic coatings. The characterization was performed by optical and scanning electron microscopy, X-ray diffraction, and X-ray reflectometry. Coatings with different colors of interference were obtained. There were no significant changes in the surface morphology and roughness after heat treatment of 500°C. Heat treated coatings have different proportions of the crystalline phases, depending on the voltage of anodic oxidation and the temperature of the heat treatment.

Effect of Solution Treatment Temperature on Tensile Strength of Al-Mg-Si Alloy

2015 ◽  
Vol 819 ◽  
pp. 39-44 ◽  
Author(s):  
Shamsul Baharin Jamaludin ◽  
Mohd Hanif Abdullah ◽  
Mohd Noor Mazlee ◽  
Kamarudin Hussin
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Solution Heat Treatment ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Sample Solution ◽  
Solution Treatment Temperature ◽  
Solution Treated ◽  
Heat Treated

This work examines the effect of solution heat treatment temperature on the tensile strength of Al-Mg-Si aluminum alloy. All samples were machined according to the ASTM B557. The samples were solution treated at 450°C and 530°C and followed by ageing at 160°C for 0, 5, 10, 15 and 20 hours. Tensile test was carried out on the samples after heat treatment. The results showed that the highest tensile strengths (201.69 MPa) was given by the sample solution heat treated at 530 °C for 5 hours followed by 20 hours aging at 160 °C. Whereas, the lowest tensile strength (98.52MPa) was given by the sample solution treated at 450°C for 20 hours. Tensile strength was increased with ageing process and decreased for over-aged samples.

Microstructure of Aluminum Alloys: Effect of Hardening Conditions

2019 ◽  
Author(s):  
Hülya Demirören
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloys ◽  
Present Article ◽  
Room Temperature ◽  
Solution Treatment ◽  
Heat Treatments ◽  
Water Quenching ◽  
X Ray ◽  
Edx Analysis

In the present article, aluminum and its heat treatments were expressed. Also it was investigated that the influence of quenching type after solutizing heat treatment of cast Al-8.88Si-3.38 Cu on the microstructure has been reported. Alloys were prepared by controlled melting and casting. All the alloys were solutionized at 525°C for 4 h followed by water quenching at 65°C for 1, 15, 30, 60, and 90 min, respectively, and aged at 175°C for 4 h. Then they were cooled at room temperature. It was performed SEM–EDX analysis and X-ray analysis. From the analysis, it was determined Al2Cu and Al7FeCu2 phases. It was determined that those phases reinforce the microstructure. As a result, the type of quenching after solution treatment is very important for aluminum alloys.

scholarly journals Kinetics of grain growth in Ti-2.7Al-5.7Fe-6Mo-6V alloy

2017 ◽  
Vol 53 (3) ◽  
pp. 263-270
Author(s):  
T.D. Mutava ◽  
L.A. Cornish ◽  
I. Sigalas
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Grain Growth ◽  
Solution Treatment ◽  
Beta Transus ◽  
X Ray ◽  
Solution Treated ◽  
Mean Grain Size ◽  
The Mean ◽  
Kinetics Of

The metastable (?Ti) alloy Ti-2.7Al-5.7Fe-6Mo-6V (wt%) was produced by semi-centrifugal casting of blended elemental powders. The phases were identified by X-ray diffraction (XRD), and overall composition was measured by X-ray fluorescence (XRF). The beta transus was determined by differential thermal analysis (DTA) and optical microscopy. The cast alloys were annealed at different temperatures under argon, up to 900oC, where they were in the solution-treated state, and the solution-treated alloys were aged between 400oC and 600oC. The kinetics of grain growth during heat treatment of the as-cast and solution-treated alloys was investigated by metallography, using the grain intercept method. Grain growth depended on whether the matrix was (?Ti) or (?Ti), and on the competing precipitate dissolution, or nucleation and growth processes. The as-cast alloy had a mean grain size of 19 ? 7?m, which increased to 63 ? 21?m after heat treating at 500?C for 2h. The alloy was duplex between 590?C and 800?C, and completely (?Ti) above 800?C. After solution treatment, the mean grain size was 40 ? 16 ?m, which was smaller than at the lower heat treatment temperatures. Following solution treatment, the mean grain size increased with increasing ageing temperature, up to 66 ? 22?m after 2h at 600?C. The growth exponents were lower than the 0.5 for normal grain growth in both cases, and there was an incubation period at 300?C and 400?C when the alloy was not solution-treated. Minimal grain growth was observed close to the beta transus.

scholarly journals The Effect of Co-Deposition of SiC Sub-Micron Particles and Heat Treatment on Wear Behaviour of Ni–P Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Donya Ahmadkhaniha ◽  
Lucia Lattanzi ◽  
Fabio Bonora ◽  
Annalisa Fortini ◽  
Mattia Merlin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Friction Coefficient ◽  
Wear Mechanisms ◽  
Composite Coatings ◽  
Wear Behaviour ◽  
Maximum Hardness ◽  
Sic Particles ◽  
Heat Treated ◽  
The Coefficient Of Friction ◽  
The Difference

The purpose of the study is to assess the influence of SiC particles and heat treatment on the wear behaviour of Ni–P coatings when in contact with a 100Cr6 steel. Addition of reinforcing particles and heat treatment are two common methods to increase Ni–P hardness. Ball-on-disc wear tests coupled with SEM investigations were used to compare as-plated and heat-treated coatings, both pure and composite ones, and to evaluate the wear mechanisms. In the as-plated coatings, the presence of SiC particles determined higher friction coefficient and wear rate than the pure Ni–P coatings, despite the limited increase in hardness, of about 15%. The effect of SiC particles was shown in combination with heat treatment. The maximum hardness in pure Ni–P coating was achieved by heating at 400 °C for 1 h while for composite coatings heating for 2 h at 360 °C was sufficient to obtain the maximum hardness. The difference between the friction coefficient of composite and pure coatings was disclosed by heating at 300 °C for 2 h. In other cases, the coefficient of friction (COF) stabilised at similar values. The wear mechanisms involved were mainly abrasion and tribo-oxidation, with the formation of lubricant Fe oxides produced at the counterpart.

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