The Stress Concentration Mechanism of Pores Affecting the Tensile Properties in Vacuum Die Casting Metals

Cao, Hong‐Tao; Luo, Ziwei; Wang, Yuming; Wang, Jing; Hu, Tao; Xiao, Lang; Che, Junqi

doi:10.3390/ma13133019

Cited by 21 publications

(15 citation statements)

References 34 publications

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“…The existence of micropores as soft spots within the matrix impairs the hardness. Moreover, weaker load bearing cross-section of the alloy due to the presence of micropores increases the density of stress risers/microcrack initiators in the matrix, thereby deteriorating the tensile properties [51]. However, applying FSP effectively forges most of the existing micropores (Table 2), eliminates the elemental segregations, and, as a result, improves the mechanical properties.…”

Section: Methodsmentioning

confidence: 99%

Optimizing the mechanical properties of Al-4.5Cu-xSi alloys through multi-pass friction stir processing and post-process aging

Mostafavi

Taghiabadi

Jafarzadegan

2021

Archiv.Civ.Mech.Eng

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The effect of post-process aging on the microstructure and mechanical properties of multi-pass friction stir processed (FSPed) Al-4.5Cu alloy containing Si (1, 3, and 5 wt.%) was studied. According to the results, adding Si improved the fluidity and decreased the porosity content of the alloy. The addition of Si up to 3 wt.% also enhanced the mechanical properties. However, further addition of Si up to 5 wt.% impaired the tensile properties. Applying the first pass of FSP improved the tensile strength and fracture strain of the alloy containing 3 wt.% Si by 25 and 125%, respectively. However, the second and fourth pass of FSP substantially improved the fracture strain, but deteriorated the hardness and tensile strength of the alloy containing 3 wt.% Si. Post-FSP aging at 180 °C for 8 h significantly improved the mechanical properties. For instance, compared to the as-cast condition, the hardness, tensile strength, fracture strain, and toughness of post-aged four-pass FSPed Al-4.5Cu-3Si alloy increased by 107, 108, 175, and 310%, respectively. According to the fractography results, the fracture surface morphology of Al-4.5Cu-3Si alloy changed from a quasi-cleavage mode in as-cast condition to a ductile-dimple fracture mode after post-FSP aging.

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Section: Methodsmentioning

confidence: 99%

Optimizing the mechanical properties of Al-4.5Cu-xSi alloys through multi-pass friction stir processing and post-process aging

Mostafavi

Taghiabadi

Jafarzadegan

2021

Archiv.Civ.Mech.Eng

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“…The advantageous properties could be attained only if the reinforcements are distributed homogeneously and not clustered in the matrix. According to the literature available [ 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 , 172 , 173 , 174 , 175 , 176 , 177 , 178 , 179 , 180 , 181 , 182 , 183 , 184 , 185 , 186 , 187 ], limited research has been performed on CNT-reinforced MMCs due to difficulties in fabricating and dispersion of CNTs in the matrix. Most studies investigated the fabrication methods such as the casting process and powder metallurgy for developing Mg-based alloy [ 188 , 189 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 ,…”

Section: Summary and Future Road Mapsmentioning

confidence: 99%

Carbon Nanotubes (CNTs)-Reinforced Magnesium-Based Matrix Composites: A Comprehensive Review

et al. 2020

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In recent years considerable attention has been attracted to magnesium because of its light weight, high specific strength, and ease of recycling. Because of the growing demand for lightweight materials in aerospace, medical and automotive industries, magnesium-based metal matrix nanocomposites (MMNCs) reinforced with ceramic nanometer-sized particles, graphene nanoplatelets (GNPs) or carbon nanotubes (CNTs) were developed. CNTs have excellent material characteristics like low density, high tensile strength, high ratio of surface-to-volume, and high thermal conductivity that makes them attractive to use as reinforcements to fabricate high-performance, and high-strength metal-matrix composites (MMCs). Reinforcing magnesium (Mg) using small amounts of CNTs can improve the mechanical and physical properties in the fabricated lightweight and high-performance nanocomposite. Nevertheless, the incorporation of CNTs into a Mg-based matrix faces some challenges, and a uniform distribution is dependent on the parameters of the fabricating process. The characteristics of a CNTs reinforced composite are related to the uniform distribution, weight percent, and length of the CNTs, as well as the interfacial bonding and alignment between CNTs reinforcement and the Mg-based matrix. In this review article, the recent findings in the fabricating methods, characterization of the composite’s properties, and application of Mg-based composites reinforced with CNTs are studied. These include the strategies of fabricating CNT-reinforced Mg-based composites, mechanical responses, and corrosion behaviors. The present review aims to investigate and conclude the most relevant studies conducted in the field of Mg/CNTs composites. Strategies to conquer complicated challenges are suggested and potential fields of Mg/CNTs composites as upcoming structural material regarding functional requirements in aerospace, medical and automotive industries are particularly presented.

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“…The porosity of the casts is related to the gas entrapment by the melt as it passes through the gating system. During the transition of the melt through then cross-sections and complex shapes of the cast, more significant mixing of gases and vapors with melt occurs [Cao 2019]. One of the possibilities to prevent mixing of the melt with gases is a suitable design of the gating system, starting with the correct design of the runners, through the design of the ingates to the correct design of the ventilation system [Meethum 2017, Otsuka 2014].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Porosity of Casts Produced by HPDC and VPDC Technologies

Gašpár¹,

Majerník²,

Tupaj³

et al. 2022

MM SJ

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The die casting technology enables the production of complex casts with good mechanical properties and high repeatability of the production within narrow tolerance limits. However, the casts are showing signs of porosity to some extent, which may reduce their mechanical and qualitative properties. The presented article solves the problem of reducing the porosity f the high pressure die casts by vacuuming the mold. Under constants technological parameters of casting, series of casts are being casted using the HPDC and VPDC technology. The indirect method of verifying the density and volume of individual samples is used to analyze the porosity of casts. At the same time, a macroscopic examination of the homogeneity of the casts is performed on selected samples. Macroscopic examination showed a detectable decrease in pore size and distribution in the casts. Based on the measurements, i tis proved that by using the vacuum pressure die casting process while maintaining the constant settings of the technological parameters of casting, a reduction in the porosity of the casts by an average of 24.4 % was achieved.

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The Stress Concentration Mechanism of Pores Affecting the Tensile Properties in Vacuum Die Casting Metals

Cited by 21 publications

References 34 publications

Optimizing the mechanical properties of Al-4.5Cu-xSi alloys through multi-pass friction stir processing and post-process aging

Optimizing the mechanical properties of Al-4.5Cu-xSi alloys through multi-pass friction stir processing and post-process aging

Carbon Nanotubes (CNTs)-Reinforced Magnesium-Based Matrix Composites: A Comprehensive Review

Comparison of Porosity of Casts Produced by HPDC and VPDC Technologies

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