The complex interaction between microstructural features and crack evolution during cyclic testing in heat-treated Al–Si–Mg–Cu cast alloys

The phase and morphology of precipitates in heat-treated Co-28Cr-6Mo-xC (x = 0.12, 0.15, 0.25, and 0.35mass%) alloys were investigated. The as-cast alloys were solution-treated in the temperature range of 1473 to 1623 K for 0 to 43.2 ks. Complete precipitate dissolution was observed in all four alloys, each of which had different carbon contents. The holding time for complete dissolution was greater for alloys with greater carbon content. The curve representing the boundary between the complete- and incomplete-dissolution conditions for each alloy is C shaped. Under the incomplete precipitate dissolution conditions of the Co-28Cr-6Mo-0.25C alloy, an M23C6 type carbide and a π-phase (M2T3X type carbide with β-Mn structure) were observed at 1548 to 1623 K, and starlike precipitates with a stripe pattern and with a dense appearance were both observed; the former comprised the M23C6 type carbide + γ-phase, and the latter was the π-phase. In contrast, only a blocky-dense M23C6 type carbide was observed at 1473 to 1523 K.

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Machinability aspects of heat-treated Al-(6-11)%Si cast alloys :

10.1522/030145370 ◽

2010 ◽

Cited By ~ 3

Author(s):

Yasser Zedan

Keyword(s):

Heat Treated ◽

Cast Alloys

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Effect of Magnesium and Artificial Aging on the Microstructure and Mechanical Properties of Al-Si-Mn-Mg Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.83-86.415 ◽

2009 ◽

Vol 83-86 ◽

pp. 415-420

Author(s):

S.G. Shabestari ◽

M.M. Hejazi ◽

M. Bahramifar

Keyword(s):

Mechanical Properties ◽

Quality Index ◽

Industrial Applications ◽

Maximum Value ◽

Microstructure And Mechanical Properties ◽

Heat Treated ◽

Cast Alloys ◽

Mg Addition ◽

Strength And Ductility ◽

Magnesium Addition

The effect of magnesium addition up to 0.9 wt.% on the microstructure and mechanical properties of Al-9Si-0.35Mn alloy has been investigated in both as-cast and heat treated conditions. Generally, Mg addition increases the heat treatability and strength of the alloys at the expense of the lower ductility. High levels of magnesium addition, causes the formation of large and brittle intermetallics, a slight increase in porosity and hence, a decrease in ultimate tensile strength and ductility of the cast alloys. T6 heat treatment increases the strength of the alloys up to 80 percent compared to as-cast samples. Among the studied compositions, heat treated Al-9Si-0.35Mn-0.25Mg alloy, has the maximum value of quality index and can be regarded as a promising material with the optimum mechanical properties for industrial applications.

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Influence of Nanodispersions on Properties and Microstructure Features of Cast and T6 Heat-Treated Al Si Hypoeutectic Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.192-193.76 ◽

2012 ◽

Vol 192-193 ◽

pp. 76-82

Author(s):

Iman El Mahallawi ◽

Hoda Abdelkader ◽

Laila Shehata ◽

Asmaa Amer ◽

Joachim Mayer ◽

...

Keyword(s):

Lamellar Spacing ◽

Light Metal ◽

Nano Particles ◽

Silicon Alloys ◽

Aluminum Silicon Alloys ◽

Mechanical Stirring ◽

Heat Treated ◽

Cast Alloys ◽

Semi Solid ◽

Function Relationship

Cast light metal alloys have retained their importance and unique characteristics as first candidates when cost-function relationship is considered. Hypoeutectic aluminum silicon alloys as (A356) exhibit several specific and interesting properties that qualify them to be used in many automotive and aeronautical applications. Evidence of significant enhancement in strength in the properties of Al-Si cast alloys by incorporating nano-particles have been recently presented. The present study aims at developing nano-dispersed Al-Si alloys with suitable casting methods that assure the dispersion of the nano-particles. In this work a number of cast samples of A356 were prepared by rheo-casting in a specially designed and built furnace unit allowing for the addition of the nano-particles into the molten Al-Si alloy in the semi-solid state with mechanical stirring. The microstructural features and the mechanical properties of the cast and T6 heat treated samples were investigated. The results obtained in this work showed enhancement in the mechanical strength of the nano-dispersed alloys, accompanied by significant increase in the elongation percentage, supported by evidence of refined dendrite arms length, and inter-lamellar spacing.

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Effect of Zr Addition and Aging Treatment on the Tensile Properties of Al-Si-Cu-Mg Cast Alloys

10.5772/intechopen.92814 ◽

2020 ◽

Author(s):

Jacobo Hernandez-Sandoval ◽

Mohamed H. Abdelaziz ◽

Agnes M. Samue ◽

Herbert W. Doty ◽

Fawzy H. Samuel

Keyword(s):

Yield Strength ◽

Tensile Properties ◽

Tensile Testing ◽

Quality Index ◽

Prolonged Exposure ◽

Aging Treatment ◽

Tensile Tests ◽

Heat Treated ◽

Cast Alloys ◽

Noticeable Reduction

The present study focused on the tensile properties at ambient and high temperatures of alloy 354 without and with the addition of zirconium. Tensile tests were performed on alloy samples submitted to various aging treatments, with the aim of understanding the effects of the addition made on the tensile properties of the alloy. Zirconium reacts only with Ti, Si, and Al in the alloys examined to form the phases (Al,Si)2(Zr,Ti) and (Al,Si)3(Zr,Ti). Testing at 25°C reveals that the minimum and maximum quality index values, 259 and 459 MPa, are observed for the as-cast and solution heat-treated conditions, respectively. The yield strength shows a maximum of 345 MPa and a minimum of 80 MPa within the whole range of aging treatments applied. The ultimate tensile and yield strength values obtained at room temperature for T5-treated samples stabilized at 250°C for 200 h are comparable to those of T6-treated samples stabilized under the same conditions, and higher in the case of elevated-temperature (250°C) tensile testing. Coarsening of the strengthening precipitates following such prolonged exposure at 250°C led to noticeable reduction in the strength values, particularly the yield strength, and a remarkable increase in the ductility values.

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Effect of Artificial Aging Treatment and lubrication Modes on the Machinability of A356 Cast Alloys

10.20944/preprints201912.0338.v1 ◽

2019 ◽

Author(s):

Mohamed Amine Alliche ◽

Abdelhakim Djebara ◽

Yasser Zedan ◽

Victor Songmene

Keyword(s):

Heat Treatment ◽

Cutting Force ◽

Surface Quality ◽

Feed Rate ◽

Artificial Aging ◽

Cutting Speed ◽

Chip Thickness ◽

Burr Formation ◽

Heat Treated ◽

Cast Alloys

This article discuss the effects of heat treatment on the machinability of Al-Si-Mg alloys (A356) cast alloys for as-received alloy, solution heat-treated alloy (SHT) as well as solution heat treated and then aged alloys at 155ºC, 180ºC, and 220ºC. In the course of machinability evaluation, several criteria including cutting force, surface roughness, tool wears and burr analysis (chip) were studied. The results and analysis in this work indicated that selected machinability criteria are important and necessary to effectively evaluate the machinability of A356 alloys. Machinability of both materials and tool was estimated in terms of chip thickness ratio and burr formation, roughness, cutting force and flank wear. The effects of various lubrication modes such as dry, mist and wet, cutting parameters, including cutting speed and feed rate on the machinability of A356 cast alloys were also examined. Experimental results proves that the heat treatment parameters strongly controlling the burr formation and surface quality. The results obtained indicate that better drilling performance in terms of surface quality occurs at high feed rate, dry drilling and artificial aging at T6.

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On the Elevated Temperature, Tensile Properties of Al-Cu Cast Alloys: Role of Heat Treatment

Advances in Materials Science and Engineering ◽

10.1155/2019/8247914 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15

Author(s):

A. Girgis ◽

A. M. Samuel ◽

H. W. Doty ◽

S. Valtierra ◽

F. H. Samuel

Keyword(s):

Heat Treatment ◽

High Temperature ◽

Tensile Properties ◽

Treatment Conditions ◽

Heat Treated ◽

Cast Alloys ◽

High Temperature Tensile ◽

High Temperature Tensile Properties ◽

Optimum Alloy

The present study aims to investigate the mechanical properties of a newly developed aluminum Al-6.5% Cu-based alloy, coded HT200, as well as to determine how these properties can be further improved using grain refinement and heat treatment. As a result, the effects of different heat treatments and alloying additions on the ambient and high-temperature tensile properties were examined. Three alloys were selected for this study: (i) the base HT200 alloy (coded A), (ii) the base HT200 alloy containing 0.15% Ti + 0.15% Zr (coded B), and (iii) the base HT200 alloy containing 0.15% Ti + 0.15% Zr + 0.5%Ag (coded C). The properties of the three HT200 alloys were compared with those of 319 and 356 alloys (coded D and E, respectively), subjected to the same heat treatment conditions. The results obtained show the optimum high-temperature tensile properties and Q-values for the five alloys of interest, along with the corresponding heat treatment conditions associated with these properties. It was found that the T6 heat-treated alloy B was the optimum alloy in terms of properties obtained, with values comparable to those of commercial B319.0 and A356.0 alloys.

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Effect of Fe Addition on Microstructure and Mechanical Properties of As-cast Ti49Ni51 Alloy

Materials ◽

10.3390/ma12193114 ◽

2019 ◽

Vol 12 (19) ◽

pp. 3114 ◽

Cited By ~ 1

Author(s):

Li ◽

Jia ◽

Wang ◽

Li ◽

Meng ◽

...

Keyword(s):

Mechanical Properties ◽

Cleavage Fracture ◽

High Yield ◽

High Yield Strength ◽

Microstructure And Mechanical Properties ◽

Heat Treated ◽

Low Elastic Modulus ◽

Cast Alloys ◽

Adjacent Position ◽

Fe Addition

Effect of Fe addition on microstructure and mechanical properties of as-cast Ti49Ni51 alloy were investigated. The experimental results shows the microstructures of Ti48.5Ni51Fe0.5 and Ti48Ni51Fe1 alloys are mainly composed of TiNi matrix phase (body-centered cubic, BCC), Ti3Ni4 and Ni2.67Ti1.33 phases; the microstructure of Ti47Ni51Fe2 alloy is mainly composed of BCC TiNi, Ti3Ni4, Ni2.67Ti1.33, and Ni3Ti phases; the microstructure of the Ti45Ni51Fe4 alloy is mainly composed of TiNi, Ti3Ni4 and Ni3Ti phases. The Ni3Ti nanocrystalline precipitates at the adjacent position of Ni2.67Ti1.33 phase. The Ti48.5Ni51Fe0.5 and Ti48Ni51Fe1 alloys have high yield strength and fracture strength, and can be as the engineering materials with excellent mechanical properties. In addition, the Ti48.5Ni51Fe0.5 alloy with the low elastic modulus and large elastic energy is also a good biomedical alloy of hard tissue implants. The fracture mechanism of the four alloys is mainly cleavage fracture or quasi-cleavage fracture, supplemented by ductile fracture. The experimental data obtained provide the valuable references in application of as-cast alloys and heat-treated samples in the future.

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Effect of Gallium Content and Heat Treatment on the Microstructure and Corrosion Rate of Magnesium Binary Alloys

Metals ◽

10.3390/met9090990 ◽

2019 ◽

Vol 9 (9) ◽

pp. 990 ◽

Cited By ~ 1

Author(s):

Anabel A. Hernández-Cortés ◽

José C. Escobedo-Bocardo ◽

Dora A. Cortés-Hernández ◽

José M. Almanza-Robles

Keyword(s):

Heat Treatment ◽

Corrosion Rate ◽

Calcium Phosphates ◽

Dendritic Morphology ◽

Heat Treated ◽

Weight Loss Method ◽

Cast Alloys ◽

Loss Method ◽

Gallium Content ◽

Ga Content

The microstructure and corrosion rate of as-cast and heat-treated binary Mg-Ga alloys with gallium content ranging from 0.375 to 1.5 wt. % were investigated. The corrosion rate was determined by the weight loss method using a simulated body fluid (SBF). The microstructure of the as-cast alloys showed an α-Mg matrix of dendritic morphology with intermetallic compounds Mg5Ga2 located mainly at the interdendritic regions. The fraction and size of the Mg5Ga2 particles increased with the amount of Ga in the alloy. The grain size decreased as the Ga content was increased. The products formed on the surface of the Mg-Ga alloys after immersion in SBF were MgO, Mg(OH)2, and calcium phosphates. The corrosion rate of the as-cast alloys was dependent on the Ga content. At concentrations lower than 1 wt. % the corrosion rate was similar to that of pure Mg (0.65 mm/year). However, Ga additions higher than 1 wt. % worsened the corrosion resistance. After heat treatment, the corrosion rate of Mg-Ga alloys decreased, and in the case of the alloys with Ga concentrations lower than 1 wt. %, corrosion rate was lower than that of pure Mg. Corrosion of these alloys after heat treatment was uniform.

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