Microstructure and Yield Strength Evolution of Aluminum Alloys

2019 ◽  
Author(s):  
Kai Li ◽  
Yong Du ◽  
Min Song
Keyword(s):  
Aluminum Alloys ◽  
Yield Strength ◽  
Volume Fraction ◽  
Weight Ratio ◽  
High Strength ◽  
Industrial Applications ◽  
Dynamic Strain ◽  
Dynamic Strain Ageing ◽  
Architectural Structures ◽  
Strength Modeling

Aluminum alloys are light materials with high strength-to-weight ratio, corrosion resistance, and excellent formability. Due to these advantages, they are widely used in many industrial applications such as fabrication of aeroplanes, automobiles, ships, and architectural structures. Many fabrication parameters, such as alloy composition, casting and solidification conditions, strain rate, and ageing conditions, strongly affect the microstructural features such as morphology of phases, solute-dislocation interactions, as well as size and volume fraction of strengthening precipitates, and therefore determine the mechanical properties especially yield strength. This chapter probes microstructural optimization of aluminum alloys and the relationship between their microstructures and yield strength, with emphases on recent progress in microstructural modification of Al-Si alloys, yield strength modeling of dynamic strain ageing in Al-Mg alloys, and modeling of precipitate strengthening in Al-Mg-Si(-Cu) alloys.

scholarly journals Mechanical properties, deformation and fracture mechanisms of bimodal Cu under tensile test

2021 ◽  
Vol 60 (1) ◽  
pp. 15-24
Author(s):  
Silu Liu ◽  
Yonghao Zhao
Keyword(s):  
Yield Strength ◽  
Grain Refinement ◽  
Volume Fraction ◽  
Shear Fracture ◽  
High Strength ◽  
Tensile Specimen ◽  
Deformation Mechanisms ◽  
Fracture Mechanisms ◽  
Fracture Angle ◽  
Area Reduction

Abstract Metals with a bimodal grain size distribution have been found to have both high strength and good ductility. However, the coordinated deformation mechanisms underneath the ultrafine-grains (UFGs) and coarse grains (CGs) still remain undiscovered yet. In present work, a bimodal Cu with 80% volume fraction of recrystallized micro-grains was prepared by the annealing of equal-channel angular pressing (ECAP) processed ultrafine grained Cu at 473 K for 40 min. The bimodal Cu has an optimal strength-ductility combination (yield strength of 220 MPa and ductility of 34%), a larger shear fracture angle of 83∘ and a larger area reduction of 78% compared with the as-ECAPed UFG Cu (yield strength of 410 MPa, ductility of 16%, shear fracture angle of 70∘, area reduction of 69%). Grain refinement of recrystallized micro-grains and detwinning of annealing growth twins were observed in the fractured bimodal Cu tensile specimen. The underlying deformation mechanisms for grain refinement and detwinning were analyzed and discussed.

scholarly journals Sequential Laser–Mechanical Drilling of Thick Carbon Fibre Reinforced Polymer Composites (CFRP) for Industrial Applications

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2136
Author(s):  
Sharizal Ahmad Sobri ◽  
Robert Heinemann ◽  
David Whitehead
Keyword(s):  
Carbon Fibre ◽  
Polymer Composites ◽  
Weight Ratio ◽  
High Strength ◽  
Industrial Applications ◽  
Fibre Laser ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Thrust And Torque

Carbon fibre reinforced polymer composites (CFRPs) can be costly to manufacture, but they are typically used anywhere a high strength-to-weight ratio and a high steadiness (rigidity) are needed in many industrial applications, particularly in aerospace. Drilling composites with a laser tends to be a feasible method since one of the composite phases is often in the form of a polymer, and polymers in general have a very high absorption coefficient for infrared radiation. The feasibility of sequential laser–mechanical drilling for a thick CFRP is discussed in this article. A 1 kW fibre laser was chosen as a pre-drilling instrument (or initial stage), and mechanical drilling was the final step. The sequential drilling method dropped the overall thrust and torque by an average of 61%, which greatly increased the productivity and reduced the mechanical stress on the cutting tool while also increasing the lifespan of the bit. The sequential drilling (i.e., laser 8 mm and mechanical 8 mm) for both drill bits (i.e., 2- and 3-flute uncoated tungsten carbide) and the laser pre-drilling techniques has demonstrated the highest delamination factor (SFDSR) ratios. A new laser–mechanical sequence drilling technique is thus established, assessed, and tested when thick CFRP composites are drilled.

SYNTHESIS AND CHARACTERISATION OF WOVENROVING GLASS MAT FOR EPOXYCOMPOSITES

2020 ◽  
Vol 15 (4) ◽  
Author(s):  
Mahesh Mallampati ◽  
Sreekanth Mandalapu ◽  
Govidarajulu C
Keyword(s):  
Tensile Strength ◽  
Glass Fiber ◽  
Low Cost ◽  
Weight Ratio ◽  
High Strength ◽  
Hardness Test ◽  
Industrial Applications ◽  
Sem Analysis ◽  
Low Thermal Expansion ◽  
Manufacturing Techniques

The composite materials are replacing the traditional materials because oftheir superior properties such as high tensile strength, low thermal expansion, high strength to weight ratio, low cost, lightweight, high specific modulus, renewability and biodegradability which are the most basic & common attractive features of composites that make them useful for industrial applications. The developments of new materials are on the anvil and are growing day by day. The efforts to produce economically attractive composite components have resulted in several innovative manufacturing techniques currently being used in the composites industry. Generally, composites consist of mainly two phases i.e., matrix and fiber. In this study, woven roving mats (E-glass fiber orientation (-45°/45°,0°/90°, - 45°/45°),UD450GSM)were cut in measured dimensions and a mixture of Epoxy Resin (EPOFINE-556, Density-1.15gm/cm3), Hardener (FINE HARDTM 951, Density- 0.94 gm/cm3) and Acetone [(CH3)2CO, M= 38.08 g/mol] was used to manufacture the glass fiber reinforced epoxy composite by hand lay-up method. Mechanical properties such as tensile strength, SEM analysis, hardness test, density tests are evaluated.

Impact of the Harsh Environment on E-Glass Epoxy Composite

2019 ◽  
Author(s):  
Amir Hussain Idrisi ◽  
Abdel-Hamid Ismail Mourad ◽  
Beckry Abdel-Magid ◽  
Mohammad Mozumder ◽  
Yaser Afifi
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Oil And Gas ◽  
Epoxy Composite ◽  
Uv Light ◽  
Weight Ratio ◽  
High Strength ◽  
Industrial Applications ◽  
Harsh Environment ◽  
Sustained Loads

Abstract Composite materials are being used in many industrial applications such as automobile, aerospace, marine, oil and gas industries due to their high strength to weight ratio. The long-term effect of sustained loads and environmental factors that include exposure to UV light, temperature, and moisture have been under investigation by many researchers. The major objective of this study is to evaluate the effects of harsh environment (e.g. seawater and high temperature) on the structural properties of E-glass epoxy composite materials. These effects were studied in terms of seawater absorption, permeation of salt and contaminants, chemical and physical bonds at the interface and degradation in mechanical properties. Samples were immersed in seawater at room temperature (23°C), 65°C and 90°C for the duration of 6 months. Results show that seawater absorption increased with immersion time at 23°C and 65°C, whereas the weight of the specimens decreased at 90°C. The moisture causes swelling at 23°C and 65°C and breakdown of chemical bonds between fiber and matrix at 90°C. It is observed that high temperature accelerates the degradation of the E-glass epoxy composite. At 90°C, the tensile strength of E-glass epoxy sharply decreased by 72.92% but no significant change was observed in modulus of elasticity of the composite.

Analysis of Additive Alignment in a 90∘ Elbow Channel

2020 ◽  
Vol 28 (04) ◽  
pp. 2050032
Author(s):  
Hoang Minh Khoa Nguyen ◽  
Dong-Wook Oh
Keyword(s):  
Flow Visualization ◽  
Fiber Type ◽  
Weight Ratio ◽  
High Strength ◽  
Short Fiber ◽  
Industrial Applications ◽  
Injection Molding Process ◽  
Molding Process ◽  
Corner Region ◽  
Liquid Polymer

Short-fiber reinforced polymer composites have been widely used in industrial applications due to high strength-to-weight ratio, versatile manufacturing process, and etc. The alignment of fiber type additives plays an important role in the mechanical properties of a composite material. In this paper, an injection molding process was imitated with a liquid polymer composite flow inside a [Formula: see text] elbow channel. We performed a flow visualization experiment and analyzed the additive alignment of carbon fiber flowing in the polydimethylsiloxane (PDMS) medium. By analyzing the flow visualization images, the angle changes at the corner region of the elbow channel were calculated. At the corner region, the change of passage direction leads to the change of fiber orientation. It was observed that near to the convex region, fibers have angle change values larger than the fibers traveling near to the concave region.

ARCHITECTURAL POTENTIALITY OF FREE-FORM STRUCTURES

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Anas Hameed ◽  
Hoda Al-Alwan ◽  
Nazar Oukaili
Keyword(s):  
Parametric Design ◽  
Weight Ratio ◽  
High Strength ◽  
Free Form ◽  
Form Finding ◽  
Shell System ◽  
Construction Techniques ◽  
Grid Shell ◽  
Architectural Structures ◽  
Free Form Structures

Contemporary architecture has witnessed a new innovative trend in design characterized by the creation of interesting free-flowing structures that reflect expressiveness of form and design, as well as the uniqueness of structure and approaches of construction. These fascinating structures are often perceived as landmarks that blend harmoniously into their surroundings. In the last two decades, parametric design and advanced computational tools, with prefabrication and construction techniques, enabled architects and engineers to explore new materials and methods to create such impressive structures, breaking the obsolete ways of thinking. Several examples of free-form structures lack obviously to explore architectural potentialities, that enrich the intention of architect, are still unformulated. The main objective of the present paper includes a conceptual proposal exploring the architectural potentiality of the free-form structures, focusing on form-finding possibilities through optimizing both the geometry and the mass of the structure, to generate configurations that ensure self-supported forms with stable force equilibrium. The paper introduces two simplified analytical methods to achieve the efficiency of the free-form architectural structures: the first depends on using extra materials to strengthen surfaces (such as grid shell system), and the second includes changing the geometry to achieve high “strength-to-weight” ratio (such as folding or conical self supports). By applying these methods, it is possible to explore various form-finding possibilities that contribute to the generation of characteristic landmarks with impressive structures.

Room Temperature Forming of AA7075 Aluminum Alloys: W-Temper Process

2015 ◽  
Vol 651-653 ◽  
pp. 199-204 ◽  
Author(s):  
Eneko Sáenz de Argandoña ◽  
Lander Galdos ◽  
Rafael Ortubay ◽  
Joseba Mendiguren ◽  
Xabier Agirretxe
Keyword(s):  
Aluminum Alloys ◽  
Room Temperature ◽  
Hot Stamping ◽  
Dimensional Accuracy ◽  
Industrial Condition ◽  
High Strength ◽  
Industrial Applications ◽  
Hot Forming ◽  
High Yield ◽  
Industrial Designers

As important light-weight structure material, aluminum alloys have been widely used in automotive and aerospace industries. In the last years, the manufacturing of parts with high strength and good dimensional accuracy has become the main objective in industrial applications. Within the available aluminum alloys, the 7xxx series has attract the interest of the industrial designers due to the high yield strength and ultimate tensile strength they present. However, the formability of these alloys in as-received industrial condition is very poor at room temperature and various studies are being carried out to develop efficient warm and hot forming processes to form them industrially using heated tools. In the present paper, the W-Temper forming is studied as an alternative to the warm and hot forming processes. Heat treatment temperatures and critical times are presented and an industrial B-Pillar is formed to validate the new process. In the last chapter, the final mechanical properties of the part are reported, before and after a virtual e-coat process where the W-Temper forming is compared with a hot stamping process.

scholarly journals Dynamic Strain Aging of a High Strength Steel

1967 ◽  
Vol 89 (4) ◽  
pp. 871-875 ◽  
Author(s):  
V. Goel ◽  
R. Busch ◽  
V. F. Zackay
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Dynamic Strain Aging ◽  
High Strength Steel ◽  
Strain Aging ◽  
High Strength ◽  
Important Variable ◽  
Dynamic Strain ◽  
Strength Ratio ◽  
Static Strain

The response of quenched and tempered, and ausform H-11 steel to strain aging was investigated. The straining temperature was the most important variable. Straining at elevated (up to 900 deg F) temperatures and retempering resulted in large increases (approximately 30 percent) in yield strength without the loss in ductility associated with static strain aging. The yield to ultimate strength ratio approached unity in the strain-aged steels, however, elongations of 8–12 percent were retained.

scholarly journals Numerical Modelling and Analytical Comparison of Delamination during Cryogenic Drilling of CFRP

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3995
Author(s):  
Arunachalam S. S. Balan ◽  
Chidambaram Kannan ◽  
Kunj Jain ◽  
Sohini Chakraborty ◽  
Siddharth Joshi ◽  
...  
Keyword(s):  
Numerical Models ◽  
Weight Ratio ◽  
High Strength ◽  
Industrial Applications ◽  
Reinforced Polymers ◽  
Carbon Fibre Reinforced Polymers ◽  
Subsequent Effect ◽  
Drilling Conditions ◽  
Machining Operations ◽  
Innovative Techniques

Carbon-Fibre-Reinforced Polymers (CFRPs) have seen a steady rise in modern industrial applications due to their high strength-to-weight ratio and corrosion resistance. However, their potential is being hindered by delamination which is induced on them during machining operations. This has led to the adoption of new and innovative techniques like cryogenic-assisted machining which could potentially help reduce delamination. This study is aimed at investigating the effect of cryogenic conditions on achieving better hole quality with reduced delamination. In this paper, the numerical analysis of the drilling of CFRP composites is presented. Drilling tests were performed experimentally for validation purposes. The effects of cooling conditions and their subsequent effect on the thrust force and delamination were evaluated using ABAQUS/CAE. The numerical models and experimental results both demonstrated a significant reduction in the delamination factor in CFRP under cryogenic drilling conditions.

scholarly journals Mould Components Impact on Structure and Quality of Elektron 21 Alloy

2013 ◽  
Vol 13 (2) ◽  
pp. 17-23 ◽  
Author(s):  
B. Dybowski ◽  
A. Kiełbus ◽  
R. Jarosz
Keyword(s):  
Solid Solution ◽  
Magnesium Alloys ◽  
Volume Fraction ◽  
Weight Ratio ◽  
High Strength ◽  
Shrinkage Porosity ◽  
Sand Cast ◽  
Magnesium Casting ◽  
Metallic Inclusions

Abstract Magnesium alloys due to their low density and high strength-to-weight ratio are promising material for the automotive and aerospace industries. Many elements made from magnesium alloys are produced by means of sand casting. It is essential to investigate impact of the applied mould components on the microstructure and the quality of the castings. For the research, six identical, 100x50x20mm plates has been sand cast from the Elektron 21 magnesium casting alloy. Each casting was fed and cooled in a different way: one, surrounded by mould sand, two with cast iron chills 20mm and 40mm thick applied, another two with the same chills as well as feeders applied and one with only the feeder applied. Solid solution grain size and eutectics volume fraction were evaluated quantitatively in Met-Ilo program, casting defects were observed on the scanning electron microscope Hitachi S3400N. The finest solid solution grain was observed in the castings with only the chills applied. Non metallic inclusions were observed in each plate. The smallest shrinkage porosity was observed in the castings with the feeders applied.

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