M. Refat

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Manufacturing of Nano-Surface Composites on AA7075 Using Friction Stir Processing for Military Vehicle and Transportation Applications

International Conference on Aerospace Sciences and Aviation Technology (2013)

M. Refat Mohamed Ahmed Iman El-Mahallawi

Friction stir processing (FSP) is solid state process that has been used recently for microstructural modification and surface composite development. In this study FSP has been used to incorporate Al2O3 nanoparticles on the surface of AA7075 with the aim of manufacturing low density high hardness surface nanocomposites for military vehicles andtransportation applications. The Al2O3 nanoparticles were packed into grooves of 1mm width and 7.5mm depth that were machined in 15mm thick plates of AA7075. The FSP was done using FSP tool of cylindrical probe of 6mm diameter and 20mm diameter shoulder. The tool rotation rate and tool travel speed were selected based on available literature to produce uniform dispersion of Al2O3 nanoparticles. The effect of post processing heat treatment after incorporating Al2O3nanoparticles into different temper conditions of AA7075-T6 and AA7075-O was investigated. The developed nanocomposites were investigated and characterized using optical microscopy, scanning electron microscopy, and hardness testing.

Friction Stir Processing

Surface Modification

10.21608/asat.2013.22053

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The Effect of Heat Treatment on the Properties of Friction Stir Processed AA7075‐O with and without Nano Alumina Additions

M. Refat Abdelrahman Abdelmotagaly Mohamed M. Z. Ahmed El‐Mahallawi

This chapter contains sections titled: Introduction Experimental Results and Discussion Conclusions Acknowledgment

10.1002/9781119093343.ch13

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3D Printed Resonant Compliant Mechanism to Reduce Motor Torque Requirements of Machines With Cyclic Operation

ASME 2021 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (2021)

Luca Luzi Amedeo Carloni Lorenzo Agostini Riccardo Pucci M. Refat

Abstract In the last decade, additive manufacturing technologies (AMT) have spread widely in the industrial field, mostly for fast prototyping but also for the production of finished parts that need a high level of customization. With respect to the well-established material subtractive technologies (MST), some limitations due to component shape can be overcome with AMT. Topology optimization (TO) combined with AMT is a powerful tool capable of realizing components characterized by similar stiffness but smaller inertia concerning those realized with MST. This tool can be very useful in automatic machinery design in order to reduce the required motor torque. In fact, in this realm, the mechanisms are usually subjected to predominant inertial loads. Moreover, since the introduction of fuse filament deposition modeling (FDM) of continuous fiber-reinforced thermoplastics (CFRT), mechanical characteristics comparable to highperformance metal materials can be reached. Thus, rigidity and precision can be achieved as well. In addition to TO, with FDM and size optimization (SO), the designer can easily realize components characterized by a proper stiffness to be included in mechanisms to tune their dynamic mechanical characteristics. In fact, due to their ability to passively store and release mechanical energy, elastic elements can be introduced in a mechanism in order to compensate for kinetic energy variations, which drastically reduce motor torque requirements. The required elasticity can be easily introduced in the mechanism by replacing standard kinematic pairs with Compliant Joints (CJ) in the form of flexible lamina, also assuring lightness, precision and ease of realization. This paper analyzes the potentiality of FDM in combination with TO and CJ design (CJD) for the realization of automated machinery mechanisms subjected to inertial loads. A pusher mechanism is considered: the pros and cons of adopting the procedure are shown with respect to the standard procedure.

3d printed

10.1115/smasis2021-68293

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Citations (1)

Fused Filament Fabrication of Continuous Fiber-Reinforced Thermoplastics for Compliant Mechanisms

ASME 2021 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (2021)

M. Refat Luca Luzi Lorenzo Agostini Riccardo Pucci Giovanni Berselli

Abstract In the last decade composite materials, previously almost exclusively used in aerospace and automotive industries, are becoming widespread thanks to the introduction of the fused filament fabrication (FFF) process in the additive manufacturing technology. With respect to the standard and more widely used material subtractive technologies, the FFF layer-by-layer construction process is capable of manufacturing parts featuring very complex geometry. Moreover, the deposition of reinforcing filaments provides components with highperformance mechanical characteristics. Since FFF is a relatively new technology, studies are still needed to fully understand the mechanical behavior of composite materials realized with FFF and how all the process parameters (e.g., layer thickness, filament deposition direction, type of matrix and reinforcement, the interaction between matrix and reinforcement) affect the final result. This paper deals with the preliminary experimental analysis of straight beams realized in carbon-fiber-reinforced Nylon White composite material with the MarkForged MarkTwo three-dimensional printer. Envisaged application of the considered straight beams is as flexible elements in compliant mechanisms. In particular, tensile and bending tests are performed on nine different straight beam specimens in order to provide a first understanding on how the filament disposition within the sample affects its mechanical response. From the results it is found that the proper position of the reinforcement filaments provides a very effective means to tune the selective compliance of beam flexures.

Fused filament fabrication

Filament winding

10.1115/smasis2021-68331

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Effect of Heat Treatment on Friction-Stir-Processed Nanodispersed AA7075 and 2024 Al Alloys

The minerals, metals & materials series (2017)

Iman El-Mahallawi Mohamed M. Z. Ahmed Amir A. Mahdy Abdelrahman Abdelmotagaly W. Hoziefa

Friction Stir Processing

Elongation

Precipitation hardening

10.1007/978-3-319-52383-5_29

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Citations (6)

173. Efficacy of Pulsed Electromagnetic Field Therapy on Fatigue for Patients with Multiple Sclerosis: A Systematic Review and Meta-Analysis

Multiple Sclerosis and Related Disorders (2024)

Malek Mansour Ahmed Ezzat Mahmoud Elmetwalli Khalid Radwan Alsaadany Mohamed Ahmed Mufreh Amin Elkayyat

10.1016/j.msard.2024.106134

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Manufacturing of Nano‐Surface AA7075 Composites by Friction Stir Processing

Light Metals (2014)

Mohamed M. Z. Ahmed M. Refat Iman El-Mahallawi

Friction Stir Processing

10.1002/9781118888438.ch237

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Citations (6)

THE EFFECT OF AGING TREATMENT ON THE FRICTION-STIRPROCESSED AA7075 ALLOY WITH AND WITHOUT SURFACE NANO-DISPERSION

The International Conference on Applied Mechanics and Mechanical Engineering (2016)

M. Refat A. Elashery Mohamed M. Z. Ahmed Iman El-Mahallawi

Friction stir processing (FSP) is a novel processing technique that is gaining wide recognition for manufacturing nano-dispersed surfaces, which are of high specific strength, hardness, and resistance to wear and corrosion.Herein, four-passes FSP were applied on aluminum alloy 7075 (AA7075) O with and without the addition of alumina nanoparticles (Al2O3) of average size ~40nm.All FSP parameters were constant at 40mm/min transverse speed, 500rpm and tilt angle of 3 .FSP rotation direction was reversed every two passes.The friction stir processed materials were sectioned and solution treated at 515 0 C for 1.5hrs, followed by age hardening at 120 C for 12,24,46,48 and 60hrs.The effect of heat treatment regimes on microstructure, hardness and toughness was examined, as well as the fracture mode.The new friction-stir processed surfaces without and with nanodispersion showed enhancement in the hardness of the surface of the AA7075-O material (65 HV) to almost a double (100 and 140 HV) after 4 passes FSP without and with incorporating nano-alumina particles, respectively.After 48hrs aging at 120 0 C a significant enhancement in impact toughness was achieved for both the friction stir processed without and with nanodispersion (181 and 134J, respectively), compared to the reference material AA7075 in T6 condition (104J).

10.21608/amme.2016.35176

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Microstructure, Hardness and Impact Toughness of Heat-Treated Nanodispersed Surface and Friction Stir-Processed Aluminum Alloy AA7075

Journal of Materials Engineering and Performance (2016)

M. Refat A. Elashery Stefania Toschi Mohamed M. Z. Ahmed Alessandro Morri

Friction Stir Processing

Surface Modification

10.1007/s11665-016-2346-3

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Citations (30)

Production of AlSi12CuNiMg/Al2O3 Micro/Nanodispersed Surface Composites Using Friction Stir Processing for Automotive Applications