scholarly journals Impacts of Defocusing Amount and Molten Pool Boundaries on Mechanical Properties and Microstructure of Selective Laser Melted AlSi10Mg

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 73 ◽  
Author(s):  
Suyuan Zhou ◽  
Yang Su ◽  
Rui Gu ◽  
Zhenyu Wang ◽  
Yinghao Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Molten Pool ◽  
Tensile Ductility ◽  
Processing Parameters ◽  
Coarse Grain ◽  
Tensile Fracture ◽  
High Tensile Strength ◽  
Laser Melting ◽  
Tensile Fracture Surface

The influences of processing parameters such as volumetric energy density (ε) and, particularly, defocusing amount (DA) on densification, microstructure, tensile property, and hardness of the as-printed dense AlSi10Mg alloy by selective laser melting (SLM) were studied systematically. The molten pool boundaries (MPBs) were found overwhelmingly at regular and complex spatial topological structures affected by DA value to exist in two forms, while the “layer–layer” MPB overlay mutually and the “track–track” MPBs intersect to form acute angles with each other. The microstructure of MPBs exhibits a coarse grain zone near the MPBs and the characteristics of segregation of nonmetallic elements (O, Si) where the crack easily happened. The DA value (−2 to 2 mm) affected both the density and the tensile mechanical properties. High tensile strength (456 ± 14 MPa) and good tensile ductility (9.5 ± 1.4%) were achieved in the as-printed condition corresponding to DA = 0.5 mm. The tensile fracture surface features were analyzed and correlated to the influence of the DA values.

scholarly journals Microstructure and Mechanical Properties of Al-3 Vol% CNT Nanocomposites Processed by High-Pressure Torsion

2017 ◽  
Vol 62 (2) ◽  
pp. 1109-1112 ◽  
Author(s):  
H. Asgharzadeh ◽  
H.S. Kim
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Pressure ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Tensile Ductility ◽  
Tensile Tests ◽  
Tensile Fracture ◽  
Tensile Fracture Surface ◽  
Transmission Electron

Abstract Al-3 vol% CNT nanocomposites were processed by high-pressure torsion (HPT) at room temperature under the pressure in the range of 2.5-10 GPa for up to 10 turns. Optical microscopy, scanning electron microscopy, and transmission electron microscopy (TEM) were used to investigate the microstructural evolutions upon HPT. Mechanical properties of the HPT-processed disks were studied using tensile tests and microhardness measurements. The results show gradual evolutions in the density, microstructure, and hardness with increasing the number of turns and applied presure. Nanostructured and elongated Al grains with an average grain thickness of ~40 nm perpendicular to the compression axis of HPT and an aspect ratio of ~3 are formed after 10 turns under 6 GPa. Evaluating the mechanical properties of the 10-turn processed Al/CNT nanocomposites indicates a tensile strength of 321 MPa and a hardness of 122 Hv. The tensile fracture surface of the Al/CNT nanocomposite mostly demonstrates a smooth fracture manner with fine dimples resulting in a low tensile ductility of ~1.5%.

scholarly journals Microstructure and Mechanical Properties of Tungsten Inert Gas Weld Joints of Sprayed and Cast Aluminium–Lithium Alloy

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3787
Author(s):  
Chuanguang Luo ◽  
Huan Li ◽  
Yuhui Zhang ◽  
Jianguo Li ◽  
Yuanhua Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fracture Mode ◽  
Inert Gas ◽  
Tensile Fracture ◽  
Second Phase ◽  
Tensile Fracture Surface ◽  
Weld Joints ◽  
Lithium Alloy ◽  
Mixed Fracture

The weld joints of sprayed 2195-T6 and cast 2195-T8 aluminium–lithium alloy were created using tungsten inert gas with filler wire. The microstructures and mechanical properties of the weld joints were examined. The results of the microstructure analysis showed that the width of the equiaxed grain zone (EQZ) and the amount of the second phase θ’(Al2Cu) was greater in the weld joint of the cast 2195-T8 Al–Li alloy than that of the sprayed 2195-T6 Al–Li alloy. Tensile testing indicated that failures occurred in the EQZ and partially melted zone (PMZ) for both weld joints. The tensile strength and elongation of the weld joints of the sprayed 2195-T6 and cast 2195-T8 Al–Li alloys were about 68.2%, 89.7%, and 50.7% and 28.3% those of the base metal in the joint, respectively. The cast 2195-T8 Al–Li alloy joint had more pores and cracks, resulting in lower tensile strength and elongation than those in the sprayed alloy. Further, the tensile fracture surface morphology indicated that the fracture mode of the sprayed 2195-T6 Al–Li alloy was a mixed fracture mode dominated by plastic fracture and that of the cast 2195-T8 Al–Li alloy joints was a mixed fracture mode dominated by brittle fracture.

Microstructure and mechanical properties of reinforced polyamide 12 composites prepared by laser additive manufacturing

2019 ◽  
Vol 25 (6) ◽  
pp. 1127-1134 ◽  
Author(s):  
Yanhui Liu ◽  
Lingjie Zhu ◽  
Lei Zhou ◽  
Yongjiu Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Selective Laser Sintering ◽  
Tensile Fracture ◽  
Fracture Mechanisms ◽  
Strengthening Effect ◽  
Content Type ◽  
Tensile Fracture Surface ◽  
Polyamide 12 ◽  
Microstructure And Mechanical Properties

Purpose This paper aims to explore the influence of the reinforcement included either glass beads (GBs) or carbon fiber (CF) on the reinforced polyamide 12 (PA12) composite samples prepared by selective laser sintering (SLS). Design/methodology/approach In this paper, the microstructure and mechanical properties are investigated, and the results are compared with those obtained for non-reinforced pure PA12 samples prepared by SLS. Findings The tensile fracture surface of the non-reinforced pure PA12 sample presents strong micro-deformation within the crack origination zone between the melted PA12 matrix and the un-melted PA12 particle cores. As a result, the pure PA12 sample exhibits the greatest maximum elongation. The maximum tensile strength is obtained for the CF reinforced sample because of the strengthening effect of CF and the relatively good bonding between CFs and the PA12 matrix. The minimum tensile strength is obtained for the GB reinforced PA12 sample because of the relatively weak bonding between GBs and the PA12 matrix. Originality/value These results demonstrate that the characteristics of the interfaces between the reinforcement and the PA12 matrix have an important influence on the fracture mechanisms and mechanical properties of PA12 composites fabricated by SLS.

The Influence of Specific Pressure on the Organization and Properties in Liquid Forging

2012 ◽  
Vol 430-432 ◽  
pp. 598-601
Author(s):  
Chun Li ◽  
Jia Xuan Wang ◽  
Hua Qing Miao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fracture Surface ◽  
Process Parameters ◽  
Tensile Fracture ◽  
Specific Pressure ◽  
Tensile Fracture Surface ◽  
Forging Process ◽  
Fracture Surface Analysis ◽  
And Performance

In this paper, based on the liquid forging part flange LY12, the influence of specific pressure on the organization and performance of the liquid forging part was studied through microstructure, mechanical properties and tensile fracture surface analysis methods, this article also has some guiding significance to the formulation of the best liquid forging process parameters. The results show that the tensile strength, hardness and elongation of the parts raise with the specific pressure increasing, the organization has also been significant refinement and improvement.

Effect of Rare Earth Addition on Microstructure and Mechanical Properties of Al-Si Alloys: An Overview

2013 ◽  
Vol 845 ◽  
pp. 27-30 ◽  
Author(s):  
S.L. Joy-Yii ◽  
Denni Kurniawan
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Rare Earth ◽  
Earth Element ◽  
Wear Behaviour ◽  
Tensile Fracture ◽  
Tensile Fracture Surface ◽  
Primary Si ◽  
Rare Earth Addition

This paper reviews the effect of rare earth addition on aluminium-silicon (Al-Si) alloys of hypoeutectic, eutectic, and hypereutectic types. The effects of rare earth on metallurgy, tensile strength, tensile fracture surface and wear behaviour of Al-Si alloys are highlighted and discussed in this paper. It was concluded that adding rare earth element to Al-Si alloys reduces the grain size of primary Si, increases the tensile strength and decreases the friction coefficient decreases. These indicate enhanced mechanical properties for rare earth modified Al-Si alloys are likely.

Effect of Filler Dispersion on Tensile Strength and Tearing Energy of Natural Rubber (NR) Latex Films

2015 ◽  
Vol 1134 ◽  
pp. 56-60 ◽  
Author(s):  
Siti Aisyah Jarkasi ◽  
Dzaraini Kamarun ◽  
Azemi Samsuri ◽  
Amir Hashim Md Yatim
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Latex Film ◽  
High Tensile Strength ◽  
Latex Films ◽  
Optimum Amount ◽  
Dispersing Agent ◽  
Two Factors ◽  
Filler Dispersion ◽  
Tearing Energy

Fillers play important roles in enhancing mechanical properties of NR latex films. The effect of filler dispersion and amount of dispersing agent to the tensile strength and tearing energy of NR latex films were investigated in this study. The studies were carried out by (i) varying the amount of dispersing agent (Anchoid) added which is an anionic surfactant; and (ii) varying the speed of stirring during mixing of latex with compounding ingredients. It was observed that tensile strength and tearing energy were affected by both factors listed. In the case of NR latex film filled with 10 pphr of carbon black (Super Abrasion Furnace, SAF), the optimum stirring speed was 400 rpm and the optimum amount of surfactant was in the range of 5 to 10 % by weight. High tensile strength ranging from 29 - 31 MPa and high tearing energies ranging from 90.6 - 111.0 kJ/m2were achieved from optimization of these two factors; rendering their importance.

scholarly journals Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM)

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Electron Beam Melting ◽  
Rolling Direction ◽  
Laser Melting ◽  
Plate Rolling

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.

scholarly journals An experimental method to determine the intralaminar fracture toughness of high-strength carbon-fibre reinforced composite aerostructures

2018 ◽  
Vol 122 (1255) ◽  
pp. 1352-1370 ◽  
Author(s):  
H. Liu ◽  
B.G. Falzon ◽  
G. Catalanotti ◽  
W. Tan
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Crack Tip ◽  
Damage Mechanism ◽  
Calibration Method ◽  
Compact Tension ◽  
Tensile Fracture ◽  
High Tensile Strength ◽  
Physical Test ◽  
Area Method

ABSTRACTCarbon fibres with high tensile strength are being increasingly utilised in the manufacture of advanced composite aerostructures. A Modified Compact Tension (MCT) specimen is often deployed to measure the longitudinal intralaminar fracture toughness but a high tensile strength often leads to premature damage away from the crack tip. We present an approach whereby the MCT specimen is supported by external fixtures to prevent premature damage. In addition, we have developed a novel measurement technique, based on the fibre failure strain and C-scanning, to determine the crack length in the presence of surface sublaminate delamination which masks the crack tip location. A set of cross-ply specimens, with a ((90/0)s)4 layup, were manufactured from an IMS60/epoxy composite system Two different data reduction schemes, compliance calibration and the area method, are used to determine the fibre-dominated initiation and propagation intralaminar fracture toughness values. Propagation values of fracture toughness were measured at 774.9 ± 5.2% kJ/m2 and 768.5 ± 4.1% kJ/m2, when using the compliance calibration method and the area method, respectively. Scanning Electron Microscopy (SEM) is carried out on the fracture surface to obtain insight into the damage mechanism of high-tensile-strength fibre-reinforced unidirectional composites. The measured tensile fracture toughness value is used in a fully validated computational model to simulate the physical test.

Investigation of Mechanical Properties of Nanostructured Titanium Processed by Warm ECAP Followed Cold Rolling

2014 ◽  
Vol 875-877 ◽  
pp. 63-67 ◽  
Author(s):  
Dinh van Hai ◽  
Nguyen Trong Giang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Cold Rolling ◽  
Room Temperature ◽  
Pure Titanium ◽  
Rolling Process ◽  
Coarse Grain ◽  
Nanostructured Titanium

In this work, ECAP technique was combined with cold rolling process in order to enhance mechanical properties and microstructure of pure Titanium. Coarse grain (CG) Titanium with original grain size of 150 μm had been pressed by ECAP at 425oC by 4, 8 and 12 passes, respectively. This process then was followed by rolling at room temperature with 35%, 55%, and 75% rolling strains. After two steps, mechanical properties such as strength, hardness and microstructure of processed Titanium have been measured. The result indicated significant effect of cold rolling on tensile strength, hardness and microstructure of ECAP-Titanium.

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