Effect of Barium (Ba) Addition on Dry Turning of a Commercial Al-20Mg2Si-2Cu Metal Matrix Composite

The principle aim of this study was to observe the effect of machining parameters as well as the separate additions of 0.2wt% barium (Ba) on the machinability of Al-20%Mg2Si in situ metal matrix composite. Microstructure alteration, surface roughness and cutting temperature were taken into account as indices to examine the effect of modifier and machinability during dry turning. The results showed that addition of Ba as modifier reagent results in lower cutting temperature and better surface roughness due to the formation of Ba compound and modification of morphology of Mg2Si reinforcement particle

Hydroxyapatite Coating on Titanium Alloy Ti-6Al-4V with Electrophoretic Deposition (EPD) for Dental Root Application

An α+β type titanium alloy, Ti-6Al-4V, has been coated with hydroxyapatite through electrophoretic deposition (EPD) method to improve quality of the alloy surface, in order to fulfill bioactivity requirement for orthodontic application as dental roots. The deposition process was conducted by EPD at different voltages (2 volts, 5 volts, and 10 volts) and time (2 minutes and 5 minutes). After deposition, the material was heated at temperature 700oC for 1 hour using a vacuum furnace. Coated samples analysis was conducted by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) to examine coating layer morphology and its chemical composition, respectively. Experimental results showed that the voltage and time deposition gives different effects to surface coverage and thickness of hydroxyapatite layers. Optimum layer for dental roots is obtained from the voltage of 5 volts for 5 minutes with 100% surface coverage value and 45.55μm in thickness. With low voltage and short deposition time for making a uniform coating layer, this process is much cheaper than other processes, and it is predicted to be favorable for improving osseointegration of dental roots

Shell Mould Strength of Rice Husk Ash (RHA) and Bentonite Clays in Investment Casting

Investment casting process (IC) plays a major role in the modern manufacturing process in providing an economical means of mass production components with intricate shape and complex geometry as demand in various crucial applications including aerospace, automotive, military, biomedical and others. This casting technique, develop shell mould fabrication by coating the required pattern with a refractory mixture which offers the complex geometrical shape and sizes parts to be cast. However, the modern IC approach in shell mould production suffers from zircon’s cost and supply instability as it is the main material to be used. Zircon uses as refractory filler for slurry production, and also in the form of sand used as stucco particles, is favoured by the investment casting facilities and industries as it exhibits the most versatile properties such as low thermal expansion and low reactivity to the metal to be cast. During the period of zircon supply shortage, many facilities introduce several alternatives. Currently, the step taken to reduce the cost of primary slurry material is by using some alternate refractory material like, alumina, silica, to be used with zircon for shell mould production. In relation to that, several researches continue to search for alternatives approach for shell mould materials. This research introduces the alternative method in fabricating investment casting shell mould as recognized from investment casting industry located in Sungai Puar of Bukittingi Padang Indonesia. This industry employs several local resources to fabricate the shell mould. These materials consist of rice husk ash (RHA), and two types of bentonite clays. The bentonite clays were obtained nearly from Kota Payakumbuh in the western provinces. However, this industry suffers from weak shell mould strength and need to be investigated and consulted. In this paper, the investigation on shell mould strength made from rice husk ash (RHA), and bentonite clays were conducted. The strength was measured by its modulus of rupture (MOR) performed in 3 points flexural bending test. The green and fired shell mould strength was determined from five type of slurry composition. The results revealed that the highest green and fired strength obtained were 0.157 MPa and 0.361 MPa from shell mould sample C of RHA (46%) and bentonite (54%) of its composition

Influence of solution heat treatment on microstructure and tensile properties of Gd-Treated Al-15% Mg-2 Si in-situ composites

Microstructural alteration and tensile properties of Al-15% Mg2Si composite specimens was examined after addition of gadolinium (Gd) and conducting solution heat treatment. Various percentages of gadolinium (0.5, 1.0, 2.0 and 5.0 wt. % Gd) were added to the composite Al-15% Mg2Si composite. The specimens then solutionized at 500 °C for 4h followed by quenching. The results showed that regular morphology and small size of primary Mg2Si particles is achieved after addition of 1.0 wt.% Gd compared to untreated composite. Due to solutionizing effect, Mg2Si dissolution occurred which led to alter the morphology of primary Mg2Si particles to round shape. Tensile testing results revealed that enhancement in UTS and El% values owns to influence of both Gd addition and solution heat treatment on the Al-15% Mg2Si composite. The fracture surface of untreated composite depicted a cellular fracture, while the fracture surface of Gd treated and heat treated composite showed a ductile surface containing fine dimples, in which alteration of fracture mode is due to the role of Gd and heat treatment on microstructural modification, which results in reduction of potential sites for stress concentration and crack initiation areas

Premature failure analysis of forged cold back-up roll in a continuous tandem mill

In this paper, premature failure of a forged back-up roll from a continuous tandem mill was investigated. Microstructural evolutions of the spalled specimen and surface of the roll were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and ferritscopy, while hardness value of the specimen was measured by Vickers hardness testing. The results revealed that the presence of pore and MnS inclusion with spherical and oval morphologies were the main contributing factors responsible for the poor life of the back-up roll. In addition, metal pick up and subsequently strip welding on the surface of the work roll were found as the major causes of failure in work roll which led to spalling occurrence in the back-up roll. Furthermore, relatively high percentage of retained austenite, say 9%, in outer surface of the back-up roll contributed spalling due to conversion of this meta-stable phase to martensite and creation of volume expansion on the outer surface through work hardening during mill campaign

Single-mode fiber coated with zinc oxide (ZnO) nanorods for H2 gas sensor applications

A Hydrogen (H2) gas sensor was successfully developed using optical fiber coated with Zinc Oxide (ZnO) nanorods. The single-mode fiber (SMF) used as a sensing device has been prepared by etching the SMF fiber and coated with ZnO nanorods. The etching of the fiber was performed using hydrofluoric acid (HF) to enhance the evanescent field around the fiber core. The ZnO nanorods were prepared by hydrothermal method through seeding and growth solution technique. The diameter of cladding and core are 125 μm and 8 μm, respectively, before etching and goes down to 11μm after etching. Around 2 cm of ZnO nanorods were coated in the middle of the etched fiber. The sensing layer was characterized through Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX) and X-Ray Diffraction (XRD) to verify the properties of ZnO. The developed sensor's response and recovery time were observed to be 7 min and 3 min, respectively, for a low concentration of 0.25% H2 gas. The aim of this study is to understand the gas sensing properties towards the spectral intensity variations in etched optical fiber coated with ZnO nanorods

Effect of forging temperature on biodegradable MG-0.7%ca alloy properties for implant application

The potential of binary Mg-Ca alloy as biodegradable material is considerable interest in implant application among researchers. This research was conducted to investigate the effect of different forging temperature and forging speed on the hardness, microstructure and corrosion rate of Mg-0.7%Ca. The experiment was established by preparing the alloy sample with 0.7%wt calcium content. The forging process was carried out under four different temperature variations of 140°C, 180°C, 220°C, and 260°C ( 10°C) with two different speed;25 and 45 strokes per minute (spm). The samples microstructure was examined by optical microscope and scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX). The mechanical properties of the forged samples were measured in its hardness and plastic deformation ability along with samples cold-working percentage. The corrosion rate was determined by performing the electrochemical test in simulated body fluid. This research found that increases of forging temperature and forging speed provide a higher rate of recrystallization and Mg2Ca compound precipitation results in greater hardness, increase deformation and reduce the cold-working percentage. However, the investigated factors still led to a high corrosion rate compared to a previous study and consequently, reduce the feasibility of the alloy in implant application for biodegradable material

Hasrat Muda Sdn Bhd / Hishamudin Hasbullah ... [et al.]

As the entrepreneurs, we would like to introduce our business plan and its basic features. The idea of starting the business came to our minds because we observed that there are some imperfections in current products, which is battery manufacturing. In addition to that, for the time being this industry is considered quite new. Hence we have minimal competition over market share. We see that as an opportunity to take a piece of the industry. Because the blooming of transportation industry by the government owned companies like Proton, Perodua and Modenas, as well as government agencies such as police department, and other government agencies, we plan to tie up a tender with the government itself to assure loyal clients. The six of us decided to pull in every inch of resource we can muster to start a manufacturing company. We register the company as a private limited company under the name Hasrat Muda Sdn Bhd. consisting of the following members: