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Full-Text Articles in Engineering Science and Materials

Study Of Combustion Performance Of Al/Ptfe B/Ptfe And B/Al/Ptfe Composites, Liyun Feng Jan 2019

Study Of Combustion Performance Of Al/Ptfe B/Ptfe And B/Al/Ptfe Composites, Liyun Feng

Graduate Theses and Dissertations

Metal particles like aluminum and boron are of great interest as additives to energetic materials due to their high gravimetric and volumetric heat of combustion. However, the ignition temperatures of metals are quite high and their burning rates which depend upon the surface area of the burning metal agglomerates are quite slow. The naturally formed oxide layer on the surface of metal particles can further inhibit their ignition and combustion by limiting fuel/oxidizer transport. The boron oxide layer on boron particles is of particular interest due to the strong diffusion barrier formed by its presence. However, the ignition temperature ...


Effect Of Ultrasonic Treatment On The Microstructure And Mechanical Properties Of Al6061 And Composite, Ana S. Exime Nov 2017

Effect Of Ultrasonic Treatment On The Microstructure And Mechanical Properties Of Al6061 And Composite, Ana S. Exime

FIU Electronic Theses and Dissertations

In this study, the effect of ultrasonic treatment (UST) parameters such as amplitude, sonication time, and melt temperature on microstructure and microhardness of Al 6061 alloy is evaluated. The effect of UST on the dispersion of tungsten disulfide (WS2) and carbon nanotubes (CNT) as reinforcement particles in Al 6061 during casting is also studied. The cast Al 6061 with UST demonstrated 32% grain size reduction and 8% increase in the microhardness for optimum processing conditions. The cavitation process induced by UST is responsible for the refinement in microstructure and increase of hardness by enhancing the degassing and nucleation process ...


Aluminum/Calcium Deformation Metal-Metal Composites After Conversion To Al2ca Intermetallic Reinforcement, Charles Czahor Jan 2017

Aluminum/Calcium Deformation Metal-Metal Composites After Conversion To Al2ca Intermetallic Reinforcement, Charles Czahor

Graduate Theses and Dissertations

Deformation-processed metal-metal composites (DMMCs) provide an appealing approach for producing lightweight materials with high strength and high conductivity. DMMCs can be produced by powder metallurgy and severe plastic deformation resulting in nano-filamentary reinforcement. Al/Ca composites with monolithic construction have shown promise as next-generation overhead transmission conductors. Previous research has shown that these materials tend to form various intermetallic species when exposed to elevated temperatures resulting in the degradation of properties. This study examines the effect of using a reduced loading of Ca and intentionally converting the reinforcement to an intermetallic species to produce a material with enhanced high-temperature stability ...


Modelling The Evaporation Of Aluminum In Ti–6al–4v Alloy Melted With Electron Beam And Laser, Xuan Wang, Liang Wang, Liang S. Luo, Yan Q. Su, Xin Z. Li, Rui R. Chen, Jing J. Guo, Heng Z. Fu Oct 2016

Modelling The Evaporation Of Aluminum In Ti–6al–4v Alloy Melted With Electron Beam And Laser, Xuan Wang, Liang Wang, Liang S. Luo, Yan Q. Su, Xin Z. Li, Rui R. Chen, Jing J. Guo, Heng Z. Fu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Thermodynamic Simulation For Solidification Path In Die Casting Alloy Development, Mohamad Rusydi Mohamad Yasin, Dongke Sun, Qingyou Han Oct 2016

Thermodynamic Simulation For Solidification Path In Die Casting Alloy Development, Mohamad Rusydi Mohamad Yasin, Dongke Sun, Qingyou Han

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Effect Of Time Delay Between Etching And Adhesive Bonding (“Outlife” Time) On Lap-Shear Strength Of Aluminum Alloys Using Environmentally-Friendly P2 Etch, Josh Barkhimer, Matthew Erich, Gokul Nair Jun 2015

Effect Of Time Delay Between Etching And Adhesive Bonding (“Outlife” Time) On Lap-Shear Strength Of Aluminum Alloys Using Environmentally-Friendly P2 Etch, Josh Barkhimer, Matthew Erich, Gokul Nair

Materials Engineering

Raytheon Company currently uses a Forest Products Laboratory (FPL) paste etchant for preparing aluminum surfaces for adhesive bonding, and FPL is a source of hazardous hexavalent chromium. The goal of this study was to evaluate a less-toxic P2 paste etchant as a possible replacement. Coupons of 2024-T3, 6061-T6, and 7075-T6 grades of aluminum alloy were solvent-degreased, abrasively cleaned, and etched at room temperature using P2 paste following a strict protocol adopted from Raytheon. Coupons were then left exposed to air for assigned time intervals (or “outlife” times) of 0, 1, 4, 8, 16, and 63 or 72 hours. The aluminum ...


Experimental Study On The Fabrication Of Advanced Materials For Energy Applications Using High Energy Mechanical Milling, Ashvin Kumar Narayana Swamy Jan 2013

Experimental Study On The Fabrication Of Advanced Materials For Energy Applications Using High Energy Mechanical Milling, Ashvin Kumar Narayana Swamy

Open Access Theses & Dissertations

The reaction of aluminum (Al) powder with water has the potential for on demand hydrogen generation. Conventional Al powders, however, react with water slowly due to a highly protective oxide layer on the particle surface. Current methods for Al activation involve harmful and expensive materials. The nano-scale Al powders also remain very expensive and have problems such as a large amount of oxide on the surface. The use of aluminum in an energy generation cycle is also hindered by the fact that, although Al is the most abundant metal in the Earth's crust, its recovery from ore consumes a ...


Effect Of Process Parameter On Temperature Distribution, Microstructure, And Mechanical Properties Of Self-Reacting Friction Stir Welded Aluminum Alloy 6061-T651, Monica Adriana Torres Jan 2011

Effect Of Process Parameter On Temperature Distribution, Microstructure, And Mechanical Properties Of Self-Reacting Friction Stir Welded Aluminum Alloy 6061-T651, Monica Adriana Torres

Open Access Theses & Dissertations

Self-reacting friction stir welding is the latest FSW tool configuration developed, it employs two shoulders--one on top and one on the bottom of the workpiece-- this tool configuration offers many advantages over conventional welding techniques. However, the current lack of information and specifications limits its understanding and application. This investigation analyzed the effect of process parameters on temperature distribution, microstructure evolution, and final mechanical properties of 6061-T651 SR-FS welds. A factorial experiment was carried out, in which three-process parameters were analyzed--rotational speed, travel speed, and tool plunge force-- three levels were analyzed for each parameter, except for a tool plunge ...


Processing And Composition Effects On The Fracture Behavior Of Spray-Formed 7xxx Series Al Alloys, Mala M. Sharma, Constance W. Ziemian, Timothy J. Eden Dec 2010

Processing And Composition Effects On The Fracture Behavior Of Spray-Formed 7xxx Series Al Alloys, Mala M. Sharma, Constance W. Ziemian, Timothy J. Eden

Faculty Journal Articles

The fracture properties of high-strength spray-formed Al alloys were investigated, with consideration of the effects of elemental additions such as zinc,manganese, and chromium and the influence of the addition of SiC particulate. Fracture resistance values between 13.6 and 25.6 MPa (m)1/2 were obtained for the monolithic alloys in the T6 and T7 conditions, respectively. The alloys with SiC particulate compared well and achieved fracture resistance values between 18.7 and 25.6 MPa (m)1/2. The spray-formed materials exhibited a loss in fracture resistance (KI) compared to ingot metallurgy 7075 alloys but had an ...


Angular Dependence Of Ultrasonic Wave Propagation In A Stressed, Orthorhombic Continuum: Theory And Application To The Measurement Of Stress And Texture, R. Bruce Thompson, S. S. Lee, J. F. Smith Sep 1986

Angular Dependence Of Ultrasonic Wave Propagation In A Stressed, Orthorhombic Continuum: Theory And Application To The Measurement Of Stress And Texture, R. Bruce Thompson, S. S. Lee, J. F. Smith

Ames Laboratory Publications

A theory for ultrasonic wave propagation in a symmetry plane of a biaxially stressed, orthorhombic continuum is presented. Since many of the material parameters which appear in the analysis are unknown, in particular the third‐order elastic constants of polycrystalline metals, emphasis is placed on the angular dependence of the velocities. An expansion to first order in stress‐induced anisotropy and to second order in textural anisotropy reveals terms with twofold, fourfold, and sixfold symmetry. Scenarios are proposed for using various properties of this symmetry to deduce the difference in magnitude and directions of the principal stresses independent of textural ...