On the measurement of dimensional quality of titanium alloy micro lattice struts manufactured using selective laser melting

The paper describes the measurement of the surface quality, dimensional accuracy, and cross sectional circularity of titanium alloy ( Ti-6Al-4V ) micro struts manufactured using selective laser melting. This quality is related to manufacturing and materials characteristics

Characterization of selectively laser melted Ti-6Al-4 V micro-lattice struts

This paper presents a characterization study of titanium alloy (Ti-6Al-4 V) micro-struts manufactured using selective laser melting (SLM). Previous test results from sandwich structures with titanium alloy micro-lattice cores showed that the material experienced brittle fracture failure, although it had a reasonable specific strength. Therefore, the microstructure present in the struts has been investigated in order to understand its influence on the mechanical behaviour. Conclusions on the way forward for improved mechanical behaviour, by the use of subsequent heat treatment and careful control of the manufacturing process can then be identified

EFFECT OF AGING ON THE MICROSTRUCTURES AND MECHANICAL PROPERTIES OF C102 COPPER ALLOY

Aging of copper alloy was studied at different temperature and times. Tensile test and metallurgical investigation were carried out to study the effect on mechanical properties and the microstructures of copper alloy. It was observed that peak strength was obtained by specimen aged for 4 hours at 450 oC, with yield strength of 542.38 MPa and ultimate tensile strength of 559.69 MPa. Peak strength was achieved with an increased strain field in the structure produced by coherent precipitates. The finer grain structure was observed in this stage which led to strain hardening. Lowest strength was recorded on specimen aged for 8 hours at 450 oC, with yield strength of 441.66 MPa and ultimate tensile strength of 452.24 MPa. The reduction of strength was the effect of overaging, which was due to coarsening of grain structure and elimination of precipitation coherency

Progressive collapse of titanium alloy micro-lattice structures manufactured using selective laser melting

The starting point for this research was the viability of the Selective Laser Melted (SLM) titanium alloy Ti-6Al-4V micro-lattice structure for applications in Foreign Object Impact (FOI) situations in aerospace sandwich constructions. To this end, the mechanical behaviour of single struts and the compression behaviour of micro-lattice blocks were studied. Detailed characterizations of dimensional accuracy, circularity and microstructure, as well as clarifications of deformation behaviour and failure of single manufactured struts under tensile loading were done. The variability in stress-strain curve of struts which was derived using compliance correction method was found to arise from the variations in strut diameters, due to outer surface roughness of the material. Post-manufacture heat-treatment processes improved the surface roughness and variations of strut diameters as well as the microstructure of the α/β titanium alloy, hence reduced the scatter in the stress-strain curve of single struts. The deformation of the SLM Ti-6Al-4V micro-lattice blocks with Body Centred Cubic (BCC) structure was elucidated using combined experimental studies and computational analysis. Detailed analysis of geometry and diameter variations in struts of the micro-lattice blocks were done and compared to that of single manufactured struts. Node formation and manufactured quality of the micro-lattice structure were revealed from a 45° angle diagonal plane of sectioned block. The compressive deformation behaviour of the BCC micro-lattice block structures was then studied. Effects of different manufacturing routes and parameters as well as post-manufacture treatments in the compressed micro-lattice structures were discussed. Finite element analysis was performed using a validated model of BCC micro-lattice unit cell. The progressive collapse of the micro-lattice block structure was shown to be comparable with the prediction from the finite element model of a unit cell. The numerical simulation was then used to quantify the effect of parent material properties on block collapse. In this way, the relations between SLM manufacturing route, material properties and structural performance are highlighted

Drop weight impact behaviour of sandwich panels with metallic micro lattice cores

The paper addresses the low velocity, drop weight behaviour of small (100 mm by 100 mm) sandwich panels with CFRP skins. The main point of interest is the core material, and the focus of the paper is in the use of body centred cubic (BCC) micro lattice cores made from Ti 6Al 4V titanium alloy and 316L stainless steel manufactured using selective laser melting. The mechanical behaviour of the micro lattice core is compared to that of conventional aluminium honeycomb. The paper discusses the manufacture and characterisation of the core materials, the measurement of core properties from strut tensile tests, block compression tests and the drop weight impact performance of the panels. Impact performance is expressed in terms of panel penetration. It is shown that the current Ti 6Al 4V BCC micro lattice cores are competitive with aluminium honeycomb, but that there is scope for improvement in Ti 6Al 4V micro strut mechanical properties. The SLM manufacturing process gives lattice structures with open cell architecture, which is an advantage for aerospace applications, and the SLM process can be used to realise a variety of cell lattice geometries

Determination of Elastic Modulus Value for Selectively Laser Melted Titanium Alloy Micro-Struty

Experimental method in determination of elastic modulus (E value) for micro scale specimen can be a debated issue, in the aspect of reliability and robustness of the results. Attention shall be given to the limiting factors which influence the techniques and procedure, such as the sample’s size, properties and geometries. It is also important to incorporate the microstructural effects toward producing a more understandable results. Analysis of tensile property for titanium alloy (Ti-6Al-4V) micro-struts manufactured from selective laser melting (SLM) rapid prototyping technology is presented in this paper. The result is found comparable to a standard value and will be used in future analysis of micro-lattice performance as core material in sandwich structure

The Effect on Friction Coefficient and Wear Rate of Palm Kernel Activated Carbon-Epoxy (PKAC-E) Composite at Different Temperatures

The purpose of this study is to investigate the tribological effect on friction coefficient and wear rate of Palm Kernel Activated Carbon-Epoxy (PKAC-E) composite at different temperatures. All specimens were prepared by using compaction technique. The tribological test was carried out by using a pin-on-disc tribometer in dry sliding conditions by applying different temperatures at constant sliding speed and applied load. The worn surfaces were analyzed from the images displayed in Inverted Microscope. The results show that both COF and the wear rate of the composites is increased with temperatures. Some adhesive and abrasive wear types were seen on the worn surfaces

Inbound Tourism In Malaysia: Unlocking the potential traveling experience of European and Oceanian Tourists

This study explores the memorable traveling experience (MTE) of 143 tourists from Europe and Oceanian in Malaysia. The researchers conducted a survey to investigate the factors that influence their revisit intention to Malaysia as an attractive destination. Partial least square structural equation modeling (SEM-PLS) results indicated that tourist attitudes, destination images, electronic Word of Mouth (eWOM), and perceived quality have positive and significant influences on travel intention. However, the eWOM failed to mediate the tourists’ attitudes, perceived quality, and destination image towards their revisit intentions.     Keywords: eWOM, Malaysia, Memorable Travelling Experience, Revisit Intentions eISSN: 2398-4287 © 2022. The Authors. Published for AMER ABRA CE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under the responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians), and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v7i21.371

Failure Behaviour Of 3D-Printed ABS Lattice Structure Under Compression

Lattice structure is a lightweight material that can be produced using the cutting edge additive layer manufacturing process or also known as 3D printing. Lattice structure material is a periodic cellular structure material that can be utilized in various applications especially as core material in sandwich structure configuration, where the ultimate aim is to be a lightweight material with load bearing capability. Researches are yet to be done to fully understand the behavior of lattice structure materials under several loading conditions such as tensile, bending and compression. The objective of this paper is to discuss the behavior of acrylonitrile-butadiene-styrene (ABS) lattice structure material that was produced using the layer by layer manufacturing, subjected to compressive load. Lattice structure specimens with dimension 20x20x20 mm3 were designed with body centered cubic (BCC) unit cells for three sets of strut diameter size. The specimens were produced using fused deposition modelling (FDM) Cubepro 3D printer, with varying default parameters of layer thickness, print strength and print pattern. All specimens were subjected to compressive load until densification stage and the stress-strain curves of the material were plotted. The compressed specimens were observed under an optical digital microscope and a common failure behavior of 3D-printed ABS lattice structure material was highlighted. It was shown that the failure of compressed lattice structure was initiated at joint node areas due to bending tensile stress. It can be concluded that this polymer material showed hybrid between stretch and bending-dominated characteristics. This is a good indicator for lightweight material with load absorbing capability. An understanding in the failure behavior of ABS lattice structure material is enriching the knowledge on this material under stress-strain condition

Comparative Evaluation Of Biodegradable Additives Of Ethyl Cellulose (EC) And Ethylene Vinyl Acetate (EVA) On Tribological Properties Of MBS Oil

The effect of biodegradable additives of Ethyl cellulose (EC) and Ethylene Vinyl Acetate (EVA) on tribological properties of oil extracted from banana peel waste of Musa Aluminata Balbisiana (MBS) was evaluated. The presence of EC and EVA at difference strength of concentration leads to reduction in COF, WSD and Ws values for MBS oil. The addition of 4.0% w/w of EC and EVA in pure MBS oil at the parameter of 27 ºC and 100 N of applied load were lead to reduction in WSD and Ws. However, unlike with the COF results, addition of EC and EVA on MBS oil did not show very significant reduction either in WSD or in Ws.Therefore, they would not effectively act as anti-wear properties. It can be inferred that, at the low temperatures and strength, EC is more effectives to lead to the reduction of COF in MBS oil than EVA. Lower COF values of MBS oil with presence of additive of EC and EVA suggest that the indicative of the formation of protective tribo-chemical film, which was promoted by the tribochemical reaction due to the rubbing action and chemical interaction of EC and EVA with MBS oil. MBS oil with addition of EC showed a very stable COF value compared to the addition of EVA is reflected to the strength of the boundary film formed by the oil on the surface. Surface morphology analysis on the spherical pin used in pin on disc in tribological procedures were shown to have a predominant wear mechanisms of adhesive and abrasive wear