The Effect of Chromium Addition on Fluidity, Microstructure and Mechanical Properties of Aluminium LM6 Cast Alloy

Ahmad, Rohanin

doi:10.18689/ijmsr-1000105

Cited by 8 publications

(3 citation statements)

References 9 publications

(17 reference statements)

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“…The addition of chromium to Al-Si-based alloys is usually limited to 0.35wt. %, and gives them mainly structural stability and increasing the recrystallization temperature, which, in turn, means increasing the level of creep resistance [20,21]. Similar to manganese, chromium changes the needle morphology of harmful iron-containing phases to a more branched one, but its negative effect on the liquid fluidity of the metal is one and a half times greater than that only of manganese [22][23][24].…”

Section: різнеmentioning

confidence: 99%

Microalloying and Modification of Cast Aluminum Alloys for Increasing their Level of Exploitation Properties at Elevated Temperatures. A Review

Voron¹,

Pruss²,

Byba³

2021

Processy litʹâ

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The work is devoted to the analysis of the most effective microalloying additives and modifiers influence on increasing the mechanical properties of Al-Si-based alloys (silumins) during their operation at elevated temperatures. It is shown that cast aluminum alloys based on the Al-Si system belong to a number of cheap and widely used heat-resistant aluminum alloys, but their level of mechanical properties is quite low, and operating temperature limits are mostly determined by 250 °C. Modification and microalloying is widely used to increase the level of operational properties of this type of alloys. In recent years, complex multicomponent modification of silumins by such elements as chromium, manganese, nickel, cobalt, titanium, zirconium and vanadium is considered to be more and more effective in strengthening, grain refinement, shape shifting of iron-containing phases, etc. Triple addition of these elements in a total amount up to 0.25 wt. % in many cases increases the efficiency of modification, compared with the addition of a single element. It is shown, that the addition of vanadium, molybdenum and tungsten helps to increase the hardness of alloys in the cast state. In this case, after hardening and two-stage aging, for alloys with molybdenum there is an increase in yield strength by 10% while maintaining the level of strength. Hafnium is considered as a promising nucleating element, the addition of which also significantly increases the resistance of recrystallization. Its addition to heat-resistant aluminum alloys can provide stabilization of mechanical properties up to 400 0 C. It is necessary to ensure the maximum possible grinding of hafnium intermetallics, especially in the presence of silicon in the alloy. Modification of aluminum alloys with scandium with the addition of titanium, zirconium or hafnium promotes the formation of Al 3 (Sc,Zr/Ti/Hf) dispersoids with a cubic crystal lattice of favorable symmetry L1 2 and a stable layered «core-shell» structure. The content of silicon in the alloy should be minimal due to the formation of harmful silicides. The addition of rare earth metals has a similar effect, but without the formation of layered structures. In this case, REM can form silicides, and can modify eutectic or primary silicon. In both cases, the addition of transition metals or REM, simultaneously with the modification of scandium alloys, increases the high-temperature stability of cast Al-Si-based aluminum alloys mechanical properties of through the formation of less active and diffusion-moving reinforcing dispersed phases.

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Section: різнеmentioning

confidence: 99%

Microalloying and Modification of Cast Aluminum Alloys for Increasing their Level of Exploitation Properties at Elevated Temperatures. A Review

Voron¹,

Pruss²,

Byba³

2021

Processy litʹâ

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“…Heat treatment to the high velocity oxygen fuel coated sample can lead to further improvement in the performance of iron alloy based coating materials. Post heat treatment of coating significantly improved the microstructure and interfacial bonding between the coating and substrate which in turn improved the characterization of the coatings [19]. Increase in time duration of annealing increased mechanical properties and coating adhesion but surface roughness was also increased [20].…”

Section: Introductionmentioning

confidence: 99%

Microstructure, mechanical and erosion wear analysis of post heat treated iron alloy based coating with varying chromium

Sharma

Das

Kumar

2021

Materialwissenschaft Werkst

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The present work focuses on the effect of annealing heat treatment on the microstructure, mechanical and erosion properties of iron alloy based coatings with varying chromium content. High velocity oxygen fuel coating method was used to deposit the coating over the substrate material 316 L stainless steel. The study was done in terms of microstructural analysis using x‐ray diffractometer, surface and cross‐sectional morphology using field emission scanning electron microscope, mechanical and erosion wear analysis. It was found that x‐ray diffractometer indicated presence of less amount of titanium dioxide (TiO2) and silicon dioxide (SiO2) after heat treatment. However, the peaks of hardened phase of diironylidenetitanium (Fe2Ti) and iron‐chromium (Fe−Cr) was increased. Addition of chromium up to 10 wt. % improved the hardness and adhesion pull of strength by 16 % and 62 % respectively. On the other side heat treatment of iron alloy based coating having 10 wt. % chromium increased the hardness and adhesion pull off strength by 17.3 % and 35 % respectively. The erosion wear rate was also decreased with the annealing process. The study shows that the annealing process increases hardness and adhesion pull off strength but decreases porosity and erosion wear rate.

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“…Moreover, aspects such as grain size and morphology, microstructure features, and the presence of intermetallic particles are used to correlate the positive effect of Cr on mechanical properties, wear, and corrosion behavior. [ 5,24,25 ] Although there are studies focusing on the metallurgical and mechanical characteristics of Al‐based alloys with Cr additions, the lack of information on as‐cast Al–Si alloys with different Si:Cr ratios and the correlation with solidification conditions and microstructure formation have motivated the current study. The aim of this work is to investigate the effects of Cr additions (0.25 and 0.4 wt%) on the solidification parameters (tip growth rate, liquid thermal gradient, and cooling rate), microstructure features (macrostructure and microstructure), and mechanical properties (hardness, tensile, and dry‐wear responses) of two as‐cast Al–3%Si and Al–7%Si alloys containing Fe as impurity.…”

Section: Introductionmentioning

confidence: 99%

Microstructure, Hardness, Tensile Strength, and Sliding Wear of Hypoeutectic Al–Si Cast Alloys with Small Cr Additions and Fe‐Impurity Content

2021

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The extensive application of Al-Si alloys in the foundry industry is due to their enhanced metallurgical aspects such as excellent castability, improved mechanical properties, recyclability, and high strength-to-weight ratio when compared with cast-iron alloys. [1] Despite these advantages, modern industry requires alloys with enlarged responses related to high tribology and corrosion resistances, especially for automotive, aeronautical, and aerospace applications. [2][3][4][5][6] The as-cast microstructure of Al-Si hypoeutectic alloys generally shows a dendritic structure with isolated Si and impurities as secondary phases in the interdendritic regions. The most deleterious feature related to Al-Si cast alloys is the presence of Fe that frequently appears as an impurity in conventional casting processes. Due to the low solid solubility in the α-Al matrix, Fe is segregated into the liquid during solidification and forms intermetallic compounds. Several works have shown that the presence of Fe in Al-Si cast alloys negatively changes the mechanical properties associated with the ductility due to the needle-like morphology and brittleness of the β-Al 5 FeSi (β-phase, monoclinic). [7][8][9][10][11] The βphase formation depends not only on the Fe content but also on the cooling rate conditions during solidification evolution, as reported in some works. [12][13][14] In general, the amount of β-phase increases, whereas the solidification rate decreases, mainly in those ranges observed in conventional casting processes. To solve the problem, additions of transition metals, such as Mn, Cr, Zr, Ni, Be, V, Co, and Ti, are used to change the morphology of the β-particles. Among these elements, Mn is often used for this purpose due to its effectiveness. According to Shabestari and collaborators, [15,16] small additions of Mn can avoid the β-phase formation, inducing the formation of other less harmful intermetallics. Cao and Campbel [17] and Bidmeshki et. al [18] have confirmed that a Mg:Fe ratio up to 0.5 changes the morphology of the β-particles from needle-like to star-like polygonal in Al-Si alloys.Similarly, the effects of Cr and mixtures with other elements on the microstructure and mechanical properties have been evaluated by several authors. As the atomic radius, crystal structure, and atomic number of Cr and Mn are close, it might be expected that Cr would have an efficient behavior to modify and/or eliminate the β-phase. [19] Li et al. [20] verified the formation of α-Al (Fe, Cr)Si phases after addition of 0.5% Cr to an Al-Si piston alloy with 0.8% Fe. Yang et al. [21] investigated the effect of different Cr additions to the microstructure and mechanical properties of a eutectic Al-Si alloy and demonstrated that the conversion from β-Al 5 FeSi to α-Al(Fe, Cr)Si improved mechanical responses, especially in terms of ductility. A work reported by Grushko and Pavlyuchkov [22] observed identical positive variation

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The Effect of Chromium Addition on Fluidity, Microstructure and Mechanical Properties of Aluminium LM6 Cast Alloy

Cited by 8 publications

References 9 publications

Microalloying and Modification of Cast Aluminum Alloys for Increasing their Level of Exploitation Properties at Elevated Temperatures. A Review

Microalloying and Modification of Cast Aluminum Alloys for Increasing their Level of Exploitation Properties at Elevated Temperatures. A Review

Microstructure, mechanical and erosion wear analysis of post heat treated iron alloy based coating with varying chromium

Microstructure, Hardness, Tensile Strength, and Sliding Wear of Hypoeutectic Al–Si Cast Alloys with Small Cr Additions and Fe‐Impurity Content

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