Displaying publications 1 - 20 of 31 in total

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  1. Yusof Abdullah, Mohd Reusmaazran Yusof, Azali Muhammad, Nadira Kamarudin, Paulus, Wilfred Sylvester, Nurazila Mat Zali, et al.
    MyJurnal
    The preparation, physical and mechanical properties of Al/B4C composites with 5 and 10 wt.% reinforcement content were investigated. In order to obtain the feedstock with a low powder loading, B4C mixtures containing fine powders were investigated to obtain the optimal particle packing. The experimental results indicated that the fine containing 5 and 10 wt.% particles are able to prepare the feedstock with a good flowability. The composites fabricated by powder metallurgy have low densities and homogeneous microstructures. Additionally there is no interface reaction observed between the reinforcement and matrix by XRD analysis. The hardness of Al/B4C composites prepared by powder metallurgy was high.
    Matched MeSH terms: Metallurgy
  2. Siswanto WA, Anggono AD, Omar B, Jusoff K
    ScientificWorldJournal, 2014;2014:301271.
    PMID: 25165738 DOI: 10.1155/2014/301271
    The aim of this work is to improve the accuracy of cold stamping product by accommodating springback. This is a numerical approach to improve the accuracy of springback analysis and die compensation process combining the displacement adjustment (DA) method and the spring forward (SF) algorithm. This alternate hybrid method (HM) is conducted by firstly employing DA method followed by the SF method instead of either DA or SF method individually. The springback shape and the target part are used to optimize the die surfaces compensating springback. The hybrid method (HM) algorithm has been coded in Fortran and tested in two- and three-dimensional models. By implementing the HM, the springback error can be decreased and the dimensional deviation falls in the predefined tolerance range.
    Matched MeSH terms: Metallurgy/methods*
  3. Mohammed MN, Omar MZ, Salleh MS, Alhawari KS, Kapranos P
    ScientificWorldJournal, 2013;2013:752175.
    PMID: 24194689 DOI: 10.1155/2013/752175
    Semisolid metal (SSM) processing or thixoforming is widely known as a technology that involves the formation of metal alloys between solidus and liquidus temperatures. For the procedure to operate successfully, the microstructure of the starting material must consist of solid near-globular grains surrounded by a liquid matrix and a wide solidus-to-liquidus transition area. Currently, this process is industrially successful, generating a variety of products with high quality parts in various industrial sectors. Throughout the years since its inception, a number of technologies to produce the appropriate globular microstructure have been developed and applied worldwide. The main aim of this paper is to classify the presently available SSM technologies and present a comprehensive review of the potential mechanisms that lead to microstructural alterations during the preparation of feedstock materials for SSM processing.
    Matched MeSH terms: Metallurgy/methods*
  4. Hu SJ, Kandaiya S
    Health Phys, 1985 Nov;49(5):1003-7.
    PMID: 4066325
    Matched MeSH terms: Metallurgy*
  5. Zakaria MY, Sulong AB, Muhamad N, Raza MR, Ramli MI
    Mater Sci Eng C Mater Biol Appl, 2019 Apr;97:884-895.
    PMID: 30678979 DOI: 10.1016/j.msec.2018.12.056
    Titanium-ceramic composites are potential implant material candidates because of their unique mechanical properties and biocompatibility. This review focused on the latest advancement in processing of titanium-ceramic materials. Previously, titanium-ceramic incorporated using different coating techniques, i.e., plasma spraying and electrophoretic depositions, to enhance the biocompatibility of the implants. A major drawback in these coating methods is the growth of tissue at only the surface of the composite and might peel off over time. Recently, metal-ceramic composite was introduced via powder metallurgy method such as powder injection moulding. A porous structure can be obtained via powder metallurgy. Producing a porous titanium-ceramic structure would improve the mechanical properties, biocompatibility and tissue growth within the structure. Hence, further research needed to be done by considering the potential of powder injection moulding method which offer lower costs and more complex shapes for future implant.
    Matched MeSH terms: Metallurgy
  6. Eko Kurniawan, Tubagus N. Rohmannudin, Mohamad Rasidi Rasani, Zainuddin Sajuri, Junaidi Syarif
    Sains Malaysiana, 2018;47:811-817.
    This study aimed to investigate the effects of element diffusion on the alloying behaviour and microstructure of a Ti-10%Mo10%Cr
    alloy during sintering and furnace cooling. A theoretical calculation of the average diffusion distance for each
    element was performed to predict the alloying behaviour during sintering and furnace cooling. The Ti-10%Mo-10%Cr
    alloy was fabricated using a blended element powder metallurgy approach. Micrograph of the samples after sintering
    showed bright-circle structures and significantly decreased equiaxed structures. The number of plate-like structures
    increased with prolonged sintering time. Microstructural changes occurred because of element diffusion resulting from
    the prolonged sintering time. Moreover, the diffusion distance of each element also increased with prolonged sintering
    time. Although elements can sufficiently diffuse during both sintering and furnace cooling, the diffusion distance during
    sintering was considerably higher than that during furnace cooling for all elements. The diffusion distances of Cr and
    Mo were the highest and lowest, respectively, during sintering and furnace cooling. This study showed that alloying
    behaviour mostly occurred during sintering and was controlled by the diffusion of Mo atoms.
    Matched MeSH terms: Metallurgy
  7. Rana S, Mishra P, Wahid ZA, Thakur S, Pant D, Singh L
    J Environ Sci (China), 2020 Mar;89:47-64.
    PMID: 31892401 DOI: 10.1016/j.jes.2019.09.023
    In an era of electronics, recovering the precious metal such as gold from ever increasing piles of electronic-wastes and metal-ion infested soil has become one of the prime concerns for researchers worldwide. Biological mining is an attractive, economical and non-hazardous to recover gold from the low-grade auriferous ore containing waste or soil. This review represents the recent major biological gold retrieval methods used to bio-mine gold. The biomining methods discussed in this review include, bioleaching, bio-oxidation, bio-precipitation, bio-flotation, bio-flocculation, bio-sorption, bio-reduction, bio-electrometallurgical technologies and bioaccumulation. The mechanism of gold biorecovery by microbes is explained in detail to explore its intracellular mechanistic, which help it withstand high concentrations of gold without causing any fatal consequences. Major challenges and future opportunities associated with each method and how they will dictate the fate of gold bio-metallurgy from metal wastes or metal infested soil bioremediation in the coming future are also discussed. With the help of concurrent advancements in high-throughput technologies, the gold bio-exploratory methods will speed up our ways to ensure maximum gold retrieval out of such low-grade ores containing sources, while keeping the gold mining clean and more sustainable.
    Matched MeSH terms: Metallurgy
  8. Ostovan F, Matori KA, Toozandehjani M, Oskoueian A, Yusoff HM, Yunus R, et al.
    Materials (Basel), 2016 Feb 26;9(3).
    PMID: 28773261 DOI: 10.3390/ma9030140
    The nanomechanical properties of carbon nanotubes particulate-reinforced aluminum matrix nanocomposites (Al-CNTs) have been characterized using nanoindentation. Bulk nanocomposite specimens containing 2 wt % multiwalled CNTs (MWCNTs) were synthesized by a combination of ball milling and powder metallurgy route. It has been tried to understand the correlation between microstructural evolution particularly carbon nanotubes (CNTs) dispersion during milling and mechanical properties of Al-2 wt % nanocomposites. Maximum enhancement of +23% and +44% has been found in Young's modulus and hardness respectively, owing to well homogenous dispersion of CNTs within the aluminum matrix at longer milling time.
    Matched MeSH terms: Metallurgy
  9. Jamal NA, Tan AW, Yusof F, Katsuyoshi K, Hisashi I, Singh S, et al.
    Materials (Basel), 2016 Mar 30;9(4).
    PMID: 28773377 DOI: 10.3390/ma9040254
    In recent years, closed-cell porous Aluminum (Al) has drawn increasing attention, particularly in the applications requiring reduced weight and energy absorption capability such as in the automotive and aerospace industries. In the present work, porous Al with closed-cell structure was successfully fabricated by powder metallurgy technique using PMMA as a space holder. The effects of the amount of PMMA powder on the porosity, density, microstructure and compressive behaviors of the porous specimens were systematically evaluated. The results showed that closed-cell porous Al having different porosities (12%-32%) and densities (1.6478 g/cm³, 1.5125 g/cm³ and 1.305 g/cm³) could be produced by varying the amount of PMMA (20-30 wt %). Meanwhile, the compressive behavior results demonstrated that the plateau stress decreased and the energy absorption capacity increased with increasing amount of PMMA. However, the maximum energy absorption capacity was achieved in the closed-cell porous Al with the addition of 25 wt % PMMA. Therefore, fabrication of closed-cell porous Al using 25 wt % PMMA is considered as the optimal condition in the present study since the resultant closed-cell porous Al possessed good combinations of porosity, density and plateau stress, as well as energy absorption capacity.
    Matched MeSH terms: Metallurgy
  10. Hu SJ, Koo WK, Tan KL
    Health Phys, 1984 Feb;46(2):452-5.
    PMID: 6693279
    Matched MeSH terms: Metallurgy*
  11. Chong CS, Chong HY, Fun HK, Leong LS
    Health Phys, 1985 Nov;49(5):1008-10.
    PMID: 4066326
    Matched MeSH terms: Metallurgy*
  12. Prathumratana L, Kim R, Kim KW
    Environ Geochem Health, 2020 Mar;42(3):1033-1044.
    PMID: 30206754 DOI: 10.1007/s10653-018-0186-9
    Lead contamination in topsoil of the mining and smelting area of Mitrovica, Kosovo, was investigated for total concentrations and chemical fractions by sequential extraction analysis, mineralogical fractions by X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectrometer (SEM-EDX). The study revealed that all samples contained Pb exceeding USEPA standard of 400 mg kg-1. The highest total concentration of Pb (125,000 mg kg-1) was the soil from the former smelter. Sequential extraction results showed that the predominant form of Pb was associated with Fe-Mn oxide-bound fraction which ranged from 45.37 to 71.61% of total concentrations, while carbonate and silicate Pb-binding fractions were dominant when physical measurements (XRD and SEM-EDX) were applied. Application of Pb isotope ratios (206Pb/207Pb and 208Pb/206Pb), measured by inductively coupled plasma mass spectrometry, identified that Pb contamination is originated from similar anthropogenic source. The results reflected that the Pb contamination in the soil of this area is serious. In order to provide proper approaches on remediation and prevention of health impacts to the people in this area, a continuous monitoring and health risk assessment are recommended.
    Matched MeSH terms: Metallurgy*
  13. Ashrafi N, Azmah Hanim MA, Sarraf M, Sulaiman S, Hong TS
    Materials (Basel), 2020 Sep 15;13(18).
    PMID: 32942621 DOI: 10.3390/ma13184090
    Hybrid reinforcement's novel composite (Al-Fe3O4-SiC) via powder metallurgy method was successfully fabricated. In this study, the aim was to define the influence of SiC-Fe3O4 nanoparticles on microstructure, mechanical, tribology, and corrosion properties of the composite. Various researchers confirmed that aluminum matrix composite (AMC) is an excellent multifunctional lightweight material with remarkable properties. However, to improve the wear resistance in high-performance tribological application, hardening and developing corrosion resistance was needed; thus, an optimized hybrid reinforcement of particulates (SiC-Fe3O4) into an aluminum matrix was explored. Based on obtained results, the density and hardness were 2.69 g/cm3, 91 HV for Al-30Fe3O4-20SiC, after the sintering process. Coefficient of friction (COF) was decreased after adding Fe3O4 and SiC hybrid composite in tribology behaviors, and the lowest COF was 0.412 for Al-30Fe3O4-20SiC. The corrosion protection efficiency increased from 88.07%, 90.91%, and 99.83% for Al-30Fe3O4, Al-15Fe3O4-30SiC, and Al-30Fe3O4-20SiC samples, respectively. Hence, the addition of this reinforcement (Al-Fe3O4-SiC) to the composite shows a positive outcome toward corrosion resistance (lower corrosion rate), in order to increase the durability and life span of material during operation. The accomplished results indicated that, by increasing the weight percentage of SiC-Fe3O4, it had improved the mechanical properties, tribology, and corrosion resistance in aluminum matrix. After comparing all samples, we then selected Al-30Fe3O4-20SiC as an optimized composite.
    Matched MeSH terms: Metallurgy
  14. Siti Khuzaimah Soid, Anuar Ishak, Ioan Pop
    Sains Malaysiana, 2018;47:2907-2916.
    The problem of stagnation point flow over a stretching/shrinking sheet immersed in a micropolar fluid is analyzed
    numerically. The governing partial differential equations are transformed into a system of ordinary (similarity) differential
    equation and are then solved numerically using the boundary value problem solver (bvp4c) in Matlab software. The
    effects of various parameters on the velocity and the angular velocity as well as the skin friction coefficient and the couple
    stress are shown in tables and graphs. The noticeable results are found that the micropolar and the slip parameters
    decrease the skin friction coefficient and the couple stress in the existence of magnetic field. Dual solutions appear for
    certain range of the shrinking strength. A stability analysis is performed to determine which one of the solutions is stable.
    Practical applications include polymer extrusion, where one deals with stretching of plastic sheets and in metallurgy
    that involves the cooling of continuous strips.
    Matched MeSH terms: Metallurgy
  15. Yusof Abdullah, Mohd Reusmaazran Yusof, Nadira Kamarudin, Paulus, Wilfred Sylvester, Rusnah Mustaffa, Nurazila Mat Zali, et al.
    MyJurnal
    Al/B4C composites with 0 wt.%, 5 wt.% and 10 wt.% of B4C were prepared by powder metallurgy and their properties were characterised successfully. Investigation of the effect of milling times (4, 8, 12, 16 hours) on microstructure, phase identification, hardness and neutron attenuation coefficient of composites has been studied. The results showed that hardness increased with increased of milling time, with maximum hardness obtained at 16 hours milling time. The increment is slower as the composition of B4C increased. The hardness of Al/10%B4C, Al/5%B4C and Al/0%B4C were 81.7, 78.7 and 61.2 HRB respectively. Morphology of scanning electron microscopy (SEM) showed that microstructures play important role in controlling the hardness. Meanwhile, x-ray diffraction (XRD) analysis showed the phases and crystalline present in composites with an indication that crystalline of the grain increased as the milling time increased. Neutron absorption of Al/10%B4C composites showed that this composite has the highest attenuation coefficient, thus indicating that it is the best composites for neutron shielding.
    Matched MeSH terms: Metallurgy
  16. Rahbari, R., Hamdi, M., Farhudi, O., Yahya, R., Asmalina, M., Marzuki, Z.
    MyJurnal
    Self-propagating high-temperature synthesis (SHS) of powder compacts is a novel processing technique being developed as a route for the production of engineering ceramics and other advanced materials. The process, which is also referred to as combustion synthesis, provides energy- and cost-saving advantages over the more conventional processing routes for these materials. In the case of titanium or titanium alloy materials, prior researches employed powder metallurgy technology for preparing metal matrix composites, MMCs and laminated structures through the use of fine powders of an inert phase or phases (TiC, TiN, TiB and TiB2B ) dispersed in Ti or Ti alloy powders. The present research relates to manufacture of titanium-ceramic composites that are synthesized by combustion synthesis (SHS) and retains a multilayered composite microstructure comprising one or more titanium-based layers and one ceramic titanium carbide layers.
    Matched MeSH terms: Metallurgy
  17. Soundhar A, Zubar HA, Sultan MTBHH, Kandasamy J
    Data Brief, 2019 Apr;23:103671.
    PMID: 30788395 DOI: 10.1016/j.dib.2019.01.019
    Newly prepared titanium alloy (Ti-13Zr-13Nb (TZN)) using powder metallurgy is considered in this investigation. Titanium alloys (TZN) are used in hip and knee replacement for orthopedic implants. Conventional machining, TZN alloys produce higher tool wear rate and poor surface quality, but this can be reduced by Electrical Discharge Machining (EDM) method. Moreover, EDM produce good biological and corrosion resistant surface. In this research, experiments were conducted by considering the influential process factors such as pulse on time, pulse off time, voltage, and current. The experiments were designed based on Response Surface Methodology (RSM) of face centered central composite design. Analysis of Variance (ANOVA) was conducted to identify the significance process factors and their relation to output responses such as Electrode Wear Rate (EWR), Surface Roughness (SR) and Material Removal Rate (MRR). Further, an empirical model was developed by RSM in order to predict the output responses.
    Matched MeSH terms: Metallurgy
  18. Zain RB, Koh LS
    Dent J Malays, 1988 Nov;10(2):37-40.
    PMID: 3271126
    A study has been conducted on 198 employees of a steel-mill industry. These participants were examined for mucosal lesions in the oral cavity and including the commissures and vermillion borders of the lips. The prevalences of 16 types of lesions are reported.
    Matched MeSH terms: Metallurgy
  19. Mohd Nazree Derman, Zainal Arifin Ahmad, Hussain, Luay Bakir, Nurulakmal Mohd Sharif
    MyJurnal
    A study of wear behaviour on anodised PM aluminium matrix composites (AMC) reinforced with Saffil™ alumina short fibres was done. AMC was fabricated by powder metallurgy methods (PM) with using Al flake powders and Saffil™ alumina short fibres. AMC reinforced with 15 wt % Saffil¥ alumina short fibre was selected because it showed optimum mechanical and physical properties. Sulphuric acid anodising process was performed and the objective is to obtain suitable parameters of sulphuric acid concentration, anodising voltage and anodising time on MMC. The study of anodising process was carried out with various sulphuric acid concentrations (from 0 to 20 % volume), anodising voltage (10 V to 20 V) and anodising time (from 0 to 60 minutes) at room temperature. Scanning electron microscope (SEM) was used to investigate coating morphology and thickness. From the research, anodising voltage of 18 V and 15 % vol H2SO4 in anodising time of 60 minutes were suitable parameters for sulphuric acid anodising of this AMC. SEM showed the coating thickness around 20 Pm. From the reserch, it was found that H2SO4 anodising was able to give good coating to MMC.
    Matched MeSH terms: Metallurgy
  20. Daud, M., Mohd Kamarudin, S.R., Samsu, Z., Ripin, M.S., Sattar, M.S., Rejab, R.
    MyJurnal
    The corrosion behaviour of ternary aluminium alloy sacrificial anodes with small amount addition of tin as depassivating element in natural seawater was studied by means of conventional DC electrochemical measurements. Metallurgical microscope was employed in order to observe the changing of microstructure caused by tin present in ternary alloys. The relationship between microstructure and electrochemical results was examined and particular attention paid to the cause of the electrochemical efficiency of anode performance. The results indicate that the proper precipitates uniformly distributed of tin are influence on improving electrochemical performance of alumnium alloy anode.
    Matched MeSH terms: Metallurgy
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