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RISS 인기검색어
- 검색키워드
- 저자 : Fathallah Qods (검색결과 3 건)
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Mojtaba Dehghan,Fathallah Qods,Mahdi Gerdooei,Hamidreza Mohammadian‑Semnani 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12
In this study, the cross accumulative roll-bonding (CARB) process, as an improved technique of the conventional accumulativeroll-bonding (ARB), was conducted on the AA1050 sheet up to 10 passes in two processing modes. The specimenswere either preheated before the rolling step of CARB passes and promptly roll bonded (warm CARB) or were processedat room temperature (cold CARB). The microstructure of samples was characterized using a scanning electron microscope. The effect of intermediate heat treatment on the planar homogeneity of the mechanical properties in the CARB (and evenARB) deformed sheets has not been examined yet. Hence, the present research focuses on the comparison of the planarisotropy of tensile properties between warm and cold CARB products. Also, the uniformity of microhardness distributionthroughout the thickness of samples was evaluated. The warm CARB presented higher elongation, lower tensile strength andmicrohardness with more uniformity of the microhardness distribution, and also premier planar isotropy of the mechanicalproperties than the cold CARB.
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Simple Shear Extrusion of Al/Al2O3 Composite Prepared by Stir Casting and Hot Forging
Majed Zabihi,Fathallah Qods,Esmaeil Emadoddin 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.1
In this study, aluminum/alumina composites with 3 and 5 vol% reinforcement particles were manufactured via stir castingand hot forging; they were severely deformed by the simple shear extrusion (SSE) technique. Three SSE dies with differentdistortion angles were utilized in this work. The SSE-ed samples with α = 22.5° were then fractured after one pass, whileSSE-ed samples with α = 8 and 10° were deformed up to thirteen passes, successfully. Microstructural evolution, porositypercentage and micro hardness parameters were investigated after each process. Shear punch test was then used to evaluatethe mechanical properties. Additionally, the applied force and stress/strain distributions were evaluated by the finite elementmethod (FEM) code via ABAQUS® simulation software in different passes. Moreover, the effect of the SSE process on thefracture behavior of the commercial Al and aluminum matrix composite was studied. The results showed that the effectivestrain was increased with increasing the number of SSE passes and distortion angles, while the applied force was decreasedwith increasing the number of passes. Microstructure, bonding quality, hardness and porosity percentage were also improvedby using forging and SSE processes. During the process, ultimate shear strength was enhanced with increasing the amountsof effective strain; also, shear elongation percentage was decreased. Further, SEM observations showed that the fracturemode in the SSE-ed commercial Al sample was a typical ductile one, whereas the fracture mode was nearly shear ductilewith more flat surfaces in the Al-5 vol% Al2O3specimens.
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Esmaeil Emadoddi,Majed Zabihi,Fathallah Qods 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.1
In this present study, Aluminum with 1, 3, 5 and 7 vol% alumina composites were produced via powder metallurgy andvacuum sintering techniques, then were followed by simple shear extrusion (SSE) process. Four SSE dies with differentdistortion angles (α) were used in experimental works. The SSE-ed samples with α = 22.5° and 30° were failed whereas theSSE-ed samples with α = 8° and 10° were deformed up to three passes, successfully. Porosity measurements were carriedout by Archimedes method and microstructure evaluation of the specimens was accomplished using optical and scanningelectron microscopy. Mechanical behavior of processed samples was investigated by shear punch test, and hardness measurements. It was understood that the SSE-ed samples have good bonding at aluminum/alumina interface. It was found thatby increasing the number of SSE passes, ultimate shear strength and hardness were increased. The percentage of shearelongation and porosity content were decreased. Moreover, when the amount of α was increased, the shear strength for allsamples was improved.
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