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Article
Publication date: 5 August 2014

K. Somasundara Vinoth, R. Subramanian, S. Dharmalingam and B. Anandavel

The purpose of this research paper is to find the optimum parameters, namely, the sliding speed, applied load and percentage of silicon carbide particles (SiCp), under…

Abstract

Purpose

The purpose of this research paper is to find the optimum parameters, namely, the sliding speed, applied load and percentage of silicon carbide particles (SiCp), under which AlSi10Mg/SiCp composites experience minimum wear.

Design/methodology/approach

Wear rate (WR) of AlSi10Mg, AlSi10Mg/10SiC and AlSi10Mg/20SiC was measured using pin-on-disk equipment according to ASTM G99 standards. Response surface method was used to design the experiments, model and analyze the tribological behaviour. Tests were conducted as per Box–Beheken design of experiments. The wear mechanisms were observed using scanning electron microscope. Genetic algorithm was used to find the optimum parameters for minimum WR.

Findings

Wear mechanisms underwent changes with variation in applied load, sliding speed and per cent SiCp. An optimum wear condition was obtained when the process parameters, namely, the sliding speed, applied load and percentage of SiCp, were at 4 m/s, 10 N and 20 per cent, respectively. Combined GA-RSM approach was successfully used to predict the minimum WR condition of AlSi10Mg/SiCp composites with an accuracy of 94 per cent.

Originality/value

The tribological behaviour of AlSi10Mg/SiCp composites has been investigated in detail. A statistical WR model is proposed. This paper provides an optimum condition to design the tribo contact between steel and AlSi10Mg/SiCp composites.

Details

Industrial Lubrication and Tribology, vol. 66 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 31 August 2020

Tingting Wang, Shimin Dai, Hailong Liao and Haihong Zhu

To fabricate high performance parts, this paper aims to systematically study the pores characteristics and their formation mechanisms in selective laser melting (SLM) AlSi10Mg.

Abstract

Purpose

To fabricate high performance parts, this paper aims to systematically study the pores characteristics and their formation mechanisms in selective laser melting (SLM) AlSi10Mg.

Design/methodology/approach

Cubes of 10 × 10 × 5 mm were manufactured in different laser power, scan speed and scan space. Optical microscope (OM) and scanning electron microscopes (SEM) were used to observe morphology of pores.

Findings

Round or irregular pores were found in SLMed AlSi10Mg parts. All the round pores have smooth inner walls and locate in the melt pool. The formation mechanisms of the round pores are contributed to the evaporation of elements in the melt pool, H2O, high laser energy input and hollow powder. Irregular pores have rough inner walls. Big scan space, unevenness of the upper surface, large layer thickness, spatter and oxide are the main reasons of generating irregular pores which outside the melt pool. Instability of keyhole leads to the irregular pores locate in the bottom of keyhole mode melt pool.

Originality/value

Relationship between pores and melt pool were studied systematically for the first time. Researches of pores characteristics and their formation mechanisms in SLMed AlSi10Mg would be a valuable reference for researchers to obtain an important insight into and control the defect in SLMed Al alloy.

Details

Rapid Prototyping Journal, vol. 26 no. 9
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 20 October 2014

Manickavasagam Krishnan, Eleonora Atzeni, Riccardo Canali, Flaviana Calignano, Diego Manfredi, Elisa Paola Ambrosio and Luca Iuliano

The aim of this research is to reach a deep understanding on the effect of the process parameters of Direct Metal Laser Sintering process (DMLS) on macroscopic properties…

Abstract

Purpose

The aim of this research is to reach a deep understanding on the effect of the process parameters of Direct Metal Laser Sintering process (DMLS) on macroscopic properties (hardness and density) of AlSi10Mg parts and resulting microstructure.

Design/methodology/approach

A full factorial design of experiment (DOE) was applied to determine the most significant process parameter influencing macroscopic properties of AlSi10Mg parts manufactured by DMLS process. The analysis aims to define the optimum process parameters and deduce the process window that provides better macroscopic properties of AlSi10Mg parts. Optical microscopy observations are carried out to link the microstructure to macroscopic properties.

Findings

Macroscopic properties of DMLS parts are influenced by the change in process parameters. There is a close correlation between the geometry of scan tracks and macroscopic properties of AlSi10Mg parts manufactured by DMLS process.

Originality/value

The knowledge of utilizing optimized process parameters is important to fabricate DMLS parts with better mechanical properties. The present research based on applying experimental design is the first analysis for AlSi10Mg parts produced in DMLS process.

Details

Rapid Prototyping Journal, vol. 20 no. 6
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 June 2021

Baopeng Zhang, Xuesong Han, Changpeng Chen, Wenqi Zhang, Hailong Liao and Baijin Chen

The purpose of this study is to investigate the effect of the strut size and tilt angle on the densification behavior, surface roughness and dimensional accuracy of the…

Abstract

Purpose

The purpose of this study is to investigate the effect of the strut size and tilt angle on the densification behavior, surface roughness and dimensional accuracy of the selective laser melting AlSi10Mg lattice structure was investigated in this study. In this study, the characteristics such as the density, up-skin and down-skin roughness and dimensional accuracy of selective laser melting forming technology manufacturing (SLMed) AlSi10Mg cellular lattice structure were carried. This work reveals the effect of the strut size and tilt angle on the geometric characteristics of SLMed AlSi10Mg and is benefit for controlling the forming performance of the SLMed cellular lattice structure.

Design/methodology/approach

Based on AlSi10Mg powder, the influence of the tilt angle changed from 10° to 45° with an increment of 5° were investigated, the influence of the strut size was varied from 0.4 mm to 1.2 mm with an increment of 0.2 mm were investigated. The characteristics such as the density, up-skin and down-skin roughness, dimensional accuracy and mechanical properties of SLM-ed AlSi10Mg cellular lattice structure was carried.

Findings

Greater than 99% relative density can be achieved for different strut size when optimal process parameters are used. In the optimized process interval, the struts with a tilt angle of 10° can still be formed well, which is higher than the design limit of the inclined angle given in the related literature. The tilt angle has a significant effect on the surface roughness of the strut. The microhardness reached to 157 ± 3 HV, and the maximum compressive strength was 58.86 MPa, with the optimal process parameters.

Originality/value

In this study, the characteristics such as the density, up-skin and down-skin roughness and dimensional accuracy of SLMed AlSi10Mg cellular lattice structure were carried. With the optimal geometric parameters, the authors tested microhardness and compressive strength of the cellular lattice structure. The results of this study provide theoretical and experimental basis for the realization of high-quality manufacturing and optimization design of aluminum alloy cellular lattice structure, which will meet more diversified industrial needs.

Details

Rapid Prototyping Journal, vol. 27 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 10 June 2021

Mustafa Safa Yılmaz, Gökhan Özer, Zafer Çağatay Öter and Onur Ertuğrul

This paper aims to investigate the effects of various heat treatments on microstructure, hardness, porosity and corrosion properties of the parts.

Abstract

Purpose

This paper aims to investigate the effects of various heat treatments on microstructure, hardness, porosity and corrosion properties of the parts.

Design/methodology/approach

Hot isostatic pressing (HIP) process, various heat treatments and their combinations were applied to the AlSi10Mg parts produced by direct laser metal sintering (DMLS).

Findings

It has been found that the HIP process, which is a post-processing process, reduces the amount of porosity in DMLS-AlSi10Mg material, thus improves corrosion resistance significantly.

Originality/value

In this study, the HIP process and subsequent T6 heat treatments were applied to AlSi10Mg parts produced by the DMLS technique. The study aims to increase the corrosion resistance of AlSi10Mg parts by reducing porosity with the HIP process and by altering the microstructure with the T6 process.

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Article
Publication date: 28 January 2020

Haihua Wu, Junfeng Li, Zhengying Wei and Pei Wei

To fabricate a selective laser melting (SLM)-processed AlSi10Mg part with almost full density and free of any apparent pores, this study aims to investigate the effect of…

Abstract

Purpose

To fabricate a selective laser melting (SLM)-processed AlSi10Mg part with almost full density and free of any apparent pores, this study aims to investigate the effect of ambient argon pressure and laser scanning speed on the particles splash during the AlSi10Mg powder bed laser melting.

Design/methodology/approach

Based on the discrete element method (DEM), a 3D model of random distribution of powder particles was established, and the 3D free surface of SLM forming process was dynamically tracked by the volume of fluid, where a Gaussian laser beam acts as the energy source melting the powder bed. Through the numerical simulation and process experimental research, the effect of the applied laser power and scanning speed on the operating laser melting temperature was studied.

Findings

The process stability has a fundamental role in the porosity formation, which is process-dependent. The effect of the processing conditions on the process stability and the resultant forming defects were clarified.

Research limitations/implications

The results shows that the pores were the main defects present in the SLM-processed AlSi10Mg sample, which decreases the densification level of the sample.

Practical implications

The optimal processing parameters (argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm ) applied during laser melting can improve the quality of selective laser melting of AlSi10Mg,

Social implications

It can provide a technological support for 3D printing.

Originality/value

Based on the analysis of the pore and balling formation mechanisms, the optimal processing parameters have been obtained, which were argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm. Then, a near-fully dense sample free of any apparent pores on the cross-sectional microstructure was produced by SLM, wherein the relative density of the as-built samples is larger than 97.5%.

Details

Rapid Prototyping Journal, vol. 26 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 25 June 2020

Onur Ertuğrul, Zafer Çağatay Öter, Mustafa Safa Yılmaz, Ezgi Şahin, Mert Coşkun, Gürkan Tarakçı and Ebubekir Koç

The purpose of this paper is to evaluate the effect of post process combinations, e.g. hot isostatic pressing (HIP) only, HIP + T6 heat treatments, and T6 only, with…

Abstract

Purpose

The purpose of this paper is to evaluate the effect of post process combinations, e.g. hot isostatic pressing (HIP) only, HIP + T6 heat treatments, and T6 only, with different aging time, on surface properties, microstructure and mechanical properties of stress-relieved AlSi10Mg parts produced by direct laser metal sintering.

Design/methodology/approach

HIP process and HIP + T6 heat treatments were applied to as stress-relieved direct laser metal sintered (DMLS) AlSi10Mg parts. Aging times of 4 and 12 h are selected to examine the optimum duration. To analyze the advantages of HIP process, a T6 heat treatment with 4 h of aging was also applied. Densities, open porosities and roughness values of as stress-relieved, HIPed, HIP + T6, and T6-only samples were measured. The samples were characterized by OM and SEM together with EDX analysis. An image analysis study was made to evaluate the inner pore structure, thereby to understand the mechanical behavior.

Findings

HIP process does not cause a significant change in surface porosity; yet it has a positive influence on inner porosity. HIP process results in a microstructure of the aluminum matrix surrounded by a network of micron and nano size Si particles. Additional heat treatment results in larger particles and precipitation. After HIPing, ductility increases but strength decreases. Samples aged 4 h present improved yield and tensile strength but decreased elongation, yet samples aged for 12 h reach a combination of optimum strength and ductility. The lower level of tensile strength and ductility in T6-only condition indicates that HIP process plays a crucial role in elimination of the porosity thus improves the effectiveness of subsequent heat treatment.

Originality/value

The study investigates the effect of post-process conditions and optimizes the aging time of the T6 heat treatment after HIP process in order to obtain improved mechanical properties. The stress-relieved state was chosen as the reference to prevent distortion during HIPing or heat treatment.

Details

Rapid Prototyping Journal, vol. 26 no. 8
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 5 November 2020

Sultan AlRedha, Anton Shterenlikht, Mahmoud Mostafavi, Derreck Van Gelderen, Omar Eduardo Lopez-Botello, Luis Arturo Reyes, Patricia Zambrano and Carlos Garza

A key challenge found in additive manufacturing is the difficulty to produce components with replicable microstructure and mechanical performance in distinct orientations…

Abstract

Purpose

A key challenge found in additive manufacturing is the difficulty to produce components with replicable microstructure and mechanical performance in distinct orientations. This study aims to investigate the influence of build orientation on the fracture toughness of additively manufactured AlSi10Mg specimens.

Design/methodology/approach

The AlSi10Mg specimens were manufactured using the selective laser melting (SLM) technology. The fracture toughness was experimentally determined (under ASTM E399-09) using C(T) specimens manufactured in different orientations. The microstructure of the specimens was examined using metallography to determine the effects of grain orientation on fracture toughness.

Findings

The fracture toughness magnitude of manufactured specimens ranged between 36 and 50 MPam, which closely matched conventional bulk material and literature values regarding AlSi10Mg components. The C(T) specimens printed in the T-L orientation yielded the highest fracture toughness. The grain orientation and fracture toughness values confirm the anisotropic nature of SLM parts where the T-L-oriented specimen obtained the highest KIC value. A clear interaction between the melt pool boundaries and micro-slipping during the loading application was observed.

Originality/value

The novelty of this paper consists in elucidating the relationship between grain orientation and fracture toughness of additively manufactured AlSi10Mg specimens because of the anisotropy generated by the different melting pool boundaries and orientations in SLM. The findings show that melt pool boundaries can behave as easier pathways for cracks to propagate and subsequently reduce the fracture toughness of specimens with cracks perpendicular to the build direction.

Details

Rapid Prototyping Journal, vol. 27 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 15 August 2019

Vincent Hammond, Michael Schuch and Matthias Bleckmann

The purpose of this paper is to investigate the influence of a process interruption on the tensile properties of AlSi10Mg samples produced by selective laser melting (SLM).

Abstract

Purpose

The purpose of this paper is to investigate the influence of a process interruption on the tensile properties of AlSi10Mg samples produced by selective laser melting (SLM).

Design/methodology/approach

Using identical processing parameters, cylindrical samples were produced in either a continuous or interrupted SLM build operation. The tensile properties and microstructure of the samples were determined as a function of process type as well as orientation.

Findings

All samples produced in this paper displayed superior tensile properties to those produced in high pressure die casting. In general, the samples produced in the continuous build process had higher strengths and microhardness than those produced in the interrupted process. However, while most samples displayed random failure locations, the vertical samples produced in the interrupted build process showed a strong tendency for localized failure in the vicinity of the stoppage plane.

Originality/value

This paper demonstrated that samples produced in an interrupted build process tend to have poorer mechanical properties than those produced in a continuous process. Together, these observations highlight the importance of a suitable technique for restarting and completing an interrupted build process to ensure the production of high quality components.

Details

Rapid Prototyping Journal, vol. 25 no. 8
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 16 September 2013

S. Venkat Prasat and R. Subramanian

The purpose of this paper is to explore the use of fly ash and graphite particles as low cost reinforcing materials for improved wear resistance, enhanced mechanical…

Abstract

Purpose

The purpose of this paper is to explore the use of fly ash and graphite particles as low cost reinforcing materials for improved wear resistance, enhanced mechanical properties and reduction in density of hybrid composites.

Design/methodology/approach

The AlSi10Mg/fly ash/graphite (Al/FA/Gr) hybrid composite was synthesised by stir casting method. The dry sliding wear and friction behaviour of hybrid composites were studied using pin-on-disc machine by varying parameters like load and weight fraction of fly ash, and compared with the base metal alloy and aluminium-graphite composite. The tests were conducted with a constant sliding speed of 2 m/s and sliding distance of 2,400 m.

Findings

The hybrid composites exhibit higher hardness, higher tensile strength and lower density when compared to unreinforced alloy and aluminium-graphite composite. The incorporation of fly ash and graphite particles as reinforcements caused a reduction in the wear rate and coefficient of friction (COF) of the hybrid composites. The improvement in the tribological characteristics occured due to the load carrying capacity of hard fly ash particles and the formation of a lubricating film of graphite between the sliding interfaces. The wear rates and COF of unreinforced aluminium alloy and composites increase with an increase in the applied normal load. The wear rates and COF of hybrid composites decrease with an increase in the fly ash content. 9 wt.% fly ash and 3 wt.% graphite reinforced hybrid composite exhibited the highest wear resistance and lowest COF at all applied loads. Abrasive wear and delamination were dominant in the mild wear regime of aluminium alloy and composites. Due to subsurface deformation and crack propagation, plate-like wear debris were generated during delamination wear. In the severe wear regime, the dominant wear mechanism was adhesive wear with formation of transfer layers.

Practical implications

It is expected that these findings will contribute towards the development of lightweight and low cost aluminium products with improved tribological and mechanical properties.

Originality/value

The wear and friction data have been made available in this article for the use of Al/FA/Gr hybrid composites in tribological applications.

Details

Industrial Lubrication and Tribology, vol. 65 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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