Experimental And Numerical Characterization Of Fatigue Crack Propagation In High-Speed Railway Wheel Er8 Steel,
2021
Chulalongkorn University
Experimental And Numerical Characterization Of Fatigue Crack Propagation In High-Speed Railway Wheel Er8 Steel, Chaichayo Suetrong, Vitoon Uthaisangsuk
Journal of Metals, Materials and Minerals
In this work, characteristics of fatigue crack growth in the Paris regime of the rail wheel steel grade ER8 were investigated. Experimental crack growth tests under different cyclic loads of a compact tension (CT) specimen and corresponding FE simulations were carried out. The extended FE method (XFEM) coupled with damage evolution based on the strain energy release rate or the Paris law was applied to describe the crack propagation mechanism in the tested CT samples. Hereby, the fatigue fracture model parameters were firstly determined from the experimental data. It was found that the predicted crack growth rates agreed well with …
Effect Of Cladding Of Stellite-6 Filler Wire On The Surface Of Ss316l Alloy Through Cold Metal Arc Transfer Process,
2021
Chulalongkorn University
Effect Of Cladding Of Stellite-6 Filler Wire On The Surface Of Ss316l Alloy Through Cold Metal Arc Transfer Process, Thinesh Babu Thiagarajan, Sengottuvel Ponnusamy
Journal of Metals, Materials and Minerals
In this work, Cladding was done on SS316L alloy through the CMT process using Stellite-6 filler wire. 31 experiments were done at different welding conditions as per CCD matrix. The cladding specimens were characterized by macro and micro-study, Vickers microhardness evaluation and corrosion resistance analysis. An optical microscope, SEM-EDAX, and XRD were used to predict the structural characterizations, presence and the distributions of the elements. Based on the study higher voltage & welding speed showed appreciable hardness at the interface & cladding regions. The thickness of the interface was noted at a maximum of 190 μm. The EDS spectra showed …
Development And Characterization Of Sic Fiber Reinforced B4c Composite,
2021
Chulalongkorn University
Development And Characterization Of Sic Fiber Reinforced B4c Composite, Jitendra Kumar Sonber, Sanjib Majumdar, Vivekanand Kain
Journal of Metals, Materials and Minerals
This study is conducted to investigate the effects of silicon carbide short fiber (SiCf) reinforcement on processing and properties of boron carbide ceramic. Studies have been carried out on the hot pressing, mechanical property measurement, microstructure evolution and oxidation study of SiCf reinforced B4C composite. B4C-SiCf composites have been prepared by hot pressing at 1950℃ with varying SiCf content in the range of 10 vol% to 30 vol%. All the composites are densified to near theoretical density. It is noticed that hardness of composite is decreased and fracture toughness of composite is increased by addition of SiC fiber. Hardness of …
Facile Purification Of Locally Mined Gypsum And Its Use For Preparing Nano-Hemihydrates,
2021
Chulalongkorn University
Facile Purification Of Locally Mined Gypsum And Its Use For Preparing Nano-Hemihydrates, Luqman Ayodeji Adams, Enobong Essien, Taiwo Aiyeloro, Stella Oseyomon, John Makanjuola
Journal of Metals, Materials and Minerals
Gypsum has a wide range of applications, in interior decorations, building construction, supplements or implants in orthopaedics to mention a few. However, in many developing countries including Nigeria, there is still a large-scale importation despite huge available natural deposits. In this study, a facile method to purify locally-mined gypsum has been explored based on the mineral retrograde solubility in water. The purified gypsum was investigated for its elemental composition in comparison to the crude sample and a commercially obtained medical-grade gypsum using X-ray fluorescence (XRF). The results showed that the purified gypsum contained 94.05% CaSO4 compared with the crude which …
Efficiency Of 2-Dodecylaminopyridine For The Liquid-Liquid Extraction Of Gold(Iii) From Succinic Acid Medium,
2021
Chulalongkorn University
Efficiency Of 2-Dodecylaminopyridine For The Liquid-Liquid Extraction Of Gold(Iii) From Succinic Acid Medium, Umrao Shep, Rucha Pawar, Balasaheb Arbad
Journal of Metals, Materials and Minerals
Extractive recovery of gold(III) from succinic acid solution with high molecular weight amine: 2-dodecylaminopyridine (2-DDAP) as a new extractant in xylene has been investigated. Extraction data indicates that 5 × 10-4 mol⋅L-1 2-DDAP is a very efficient and fast extractant. Gold(III) can be effectively extracted (D = 414.16) with 2-DDAP from 0.04 M succinic acid solution. The equilibrium of gold(III) from aqueous phase of succinic acid with 2-DDAP is achieved within 60 sec. The extraction of gold(III) with 2-DDAP proceed at the interface according to ion pair formation mechanism. The best stripping solution from among the studied ones is the …
Effect Of Dc Power On The Thickness, Hardness And Adhesion Strength Of Ti-51 At% Ni Coated Ti/Tin,
2021
Chulalongkorn University
Effect Of Dc Power On The Thickness, Hardness And Adhesion Strength Of Ti-51 At% Ni Coated Ti/Tin, Ishiaka Shaibu Arudi, Esah Hamzah, Muhammad Azizi Mat Yajid, Bushroa Abdul Razak
Journal of Metals, Materials and Minerals
The coating of Ti/TiN was successfully deposited on Ti-51 at% Ni substrates by using direct current (DC) magnetron sputtering technique and the effect of different sputtering power on the thickness, surface hardness and adhesion strength of the coatings were studied. The microstructural characterization was carried out using scanning electron microscope (SEM), energy-dispersive X-ray (EDX) and X-ray diffractometer (XRD). The coating thicknesses were detected and measured using SEM. The surface hardness test was performed using microhardness tester, and the adhesion strength was carried out by scratch testing. The results showed that the TiN crystallites growth orientation, thickness, surface hardness and adhesion …
Developments Of Biodegradable Polymer Based On Polylactic Acid (Pla) With Natural Color Extracts For Packaging Film Applications,
2021
Chulalongkorn University
Developments Of Biodegradable Polymer Based On Polylactic Acid (Pla) With Natural Color Extracts For Packaging Film Applications, Worraphol Nansu, Passarawan Chaiwut, Sukunya Ross, Gareth Ross, Nungruthai Suphrom, Sararat Mahasaranon
Journal of Metals, Materials and Minerals
This research was interested in the use of natural colorants to replace hazardous synthetic pigments in the plastic polymer industry. The natural colors were selected from local plants indigenous to southeast Asia, which were Hibiscus sabdariffa roselle calyx (RS) and Caesapinia sappan Linn heartwood (SP). Natural colorant extracts were used as additives in poly(lactic acid ) (PLA). These were manufactured using a twin screws extruder and blow film extruder to obtain biodegradable thin films for use as packaging materials. Biodegradable films were characterized by color index, light barrier properties, water vapor transmission (WVTR), morphology, mechanical and chemical properties. The results …
Effects Of Delay Time And Curing Temperature On Compressive Strength And Porosity Of Ground Bottom Ash Geopolymer Mortar,
2021
Chulalongkorn University
Effects Of Delay Time And Curing Temperature On Compressive Strength And Porosity Of Ground Bottom Ash Geopolymer Mortar, Nattapong Makaratat, Sumrerng Rukzon, Prinya Chindaprasirt
Journal of Metals, Materials and Minerals
This research investigated development of ground bottom ash (GBA) for a new geopolymer material. The compressive strength and porosity of the geopolymer mortar containing GBA were tested. The GBA-based geopolymer mortar mixtures were designed by control liquid to GBA ratio for all tests. Extra water was also used to maintain the workability of geopolymer mortar. The sodium hydroxide (NaOH) concentrations of 10 M and 15 M were used. Furthermore, sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) ratios by mass such as 0.50, 1.50 and 2.50 were also used as alkali activator solutions. Effects of delay time and no-delay time, heat …
A Review Of Rice Husk Silica As A Heterogeneous Catalyst Support,
2021
Chulalongkorn University
A Review Of Rice Husk Silica As A Heterogeneous Catalyst Support, Izzati Nasir, Nadiah Ameram, Arlina Ali, Siti Roshayu Hassan, Nurul Akmar Che Zaudin, Jamil Mohamed Sapari
Journal of Metals, Materials and Minerals
The yield of amorphous silica has less residue of mineral content in rice husk (RH) and a high specific surface area through the simple alkaline extraction process at first, then acid precipitation of RH. At this time, the leaching process using alkali and calcination of RH is the best method to acquire amorphous silica with a high surface area. The different temperatures were used for the calcination of RH and continue with sodium hydroxide (NaOH) treatment by using different concentration. The sample titrated using hydrochloric acid (HCl) to extract silica. Pretreatment with acid leaching for the RH was also conducted …
Enhanced Mechanical And Thermal Properties Of Fly Ash-Based Geopolymer Composites By Wollastonite Reinforcement,
2021
Chulalongkorn University
Enhanced Mechanical And Thermal Properties Of Fly Ash-Based Geopolymer Composites By Wollastonite Reinforcement, Khanthima Hemra, Takaomi Kobayashi, Pavadee Aungkavattana, Sirithan Jiemsirilers
Journal of Metals, Materials and Minerals
The present study investigated the mechanical and thermal properties of geopolymer composite. The geopolymer composite was prepared by mixing fly ash and wollastonite with the alkaline activator, which was 6 M KOH:K2SiO3 in a mass ratio of 1:1 and a solid:liquid mass ratio of 3:2. The compressive strength at 28 days of geopolymer was 33.3 MPa and possessed the highest strength of 38.3 MPa when 30 wt% wollastonite was added. The flexural strength presented differently whereby it increased from 2.1 MPa to 6.8 MPa. It increased remarkably up to 200% with the addition of 50 wt% wollastonite. The geopolymer composites …
Raman Signal Enhancement Of Low-Cost Metal Sheet Sers With Gold Decoration,
2021
Chulalongkorn University
Raman Signal Enhancement Of Low-Cost Metal Sheet Sers With Gold Decoration, Nampueng Pangpaiboon, Kawinphob Phetnam, Sukon Kalasung, Chanunthorn Chananonawathorn, Viyapol Patthanasettakul, Mati Horprathum, Pitak Eiamchai, Noppadon Nuntawong, Saksorn Limwichean
Journal of Metals, Materials and Minerals
Surface Enhance Raman Spectroscopy (SERS) is a sensitive surface creating plasmonic resonance for the Raman scattering. SERS is considered as a powerful technique to enhance the Raman signal, when quantity of sample is limited. Recently, our lab team has discovered a low-cost SERS template fabrication, laser-engraving method, which is suitable with gold nanoparticles decoration. In this work, two different materials, zinc and copper, are used as metal sheet SERS substrate. Gold nanoparticles sputtered with 270 s of sputtering time are used as decorated noble metal. FE-SEM images illustrate the nano-in-microstructure of the engraved metal sheets. The decorated Au nanoparticles are …
Oxidation Behavior Of Sn-1 Wt% Bi Alloy In Air And Deionized Water At Room Temperature,
2021
Chulalongkorn University
Oxidation Behavior Of Sn-1 Wt% Bi Alloy In Air And Deionized Water At Room Temperature, Tanavut Naravuthichai, Patama Visuttipitukul, Sirichai Leelachao, Tachai Luangvaranunt
Journal of Metals, Materials and Minerals
Formation of tin oxides on surface Sn-1 wt% Bi alloy lapping plates causes interactions with protrusions of embedded diamond grits, and reduces the efficiency of the lapping process. The rate and type of oxide formation were investigated to understand the problem. Electrochemical analysis was performed to characterize the oxide film thickness, and x-ray photoelectron spectroscopy was performed to characterize the tin oxide species. Oxidation in air at room temperature reaches a thickness of 23 Å after 72 h. Oxidation in deionized water at room temperature has a faster growth rate, and reaches a thickness of 33 Å after 72 h. …
Mechanical Performance Of Woven Carbon Reinforced Epoxy Composites With Varied Orientation Angle,
2021
Chulalongkorn University
Mechanical Performance Of Woven Carbon Reinforced Epoxy Composites With Varied Orientation Angle, Sweety Ashish Agrawal, Someshwar Bhattacharya
Journal of Metals, Materials and Minerals
The mechanical properties of woven carbon fibre reinforced epoxy composites laminated with different orientation angle in stacking sequence were investigated. Woven fabric layers with different linear density carbon tow have been produced on modified rigid rapier sample loom and impregnated with epoxy by hand lay-up technique for composite preparation. Curing of composite was carried out at room temperature for 2 h. Five different laminar composites were prepared with different orientation angles [(0/0/0/0), 0/+30/-30/0, 0/+45/-45/0, 0/+60/-60/0 and 0/+90/-90/0]. The mechanical properties like tensile, flexural, and impact test) were analysed in both longitudinal and transverse directions. Physical properties such as density and …
Investigation Of Optimum Parameters For Rotary Friction Welding Of Aluminum Round Bars Using Three-Level Factorial Design Methodology,
2021
Chulalongkorn University
Investigation Of Optimum Parameters For Rotary Friction Welding Of Aluminum Round Bars Using Three-Level Factorial Design Methodology, Tanakorn Jantarasricha, Siridech Kunhirunbawon, Montri Wimol
Journal of Metals, Materials and Minerals
The welding process has been essential to increasing productivity in numerous industries across Thailand. There are several welding processes to choose from, and the welding process to use will be determined by the suitability of the production in that industry. Another important consideration in welding is to keep the mechanical properties of the joint area as close to the parent material workpiece as possible. This research aims to select the optimum parameter for rotary friction welding aluminum round bar AA6063-T5. That is according to the DIN 50125 type B standard test. The optimal condition consists of welding rotational speed, welding …
Synthesis And Optical Properties Of Forsterite Ceramic Pigments Using Mirror Wastes As A Flux,
2021
Chulalongkorn University
Synthesis And Optical Properties Of Forsterite Ceramic Pigments Using Mirror Wastes As A Flux, Niti Yongvanich, Natchaya Lithira, Nitchakarn Nuniead, Wanchalerm Chauyarsa
Journal of Metals, Materials and Minerals
Cobalt-doped forsterite ceramic pigments based on the formula (Mg2-2xCo2x)SiO4 (x = 0, 0.05, 0.1, 0.2) were synthesized using mirror wastes as a flux. Addition of this flux enhanced forsterite phase formation at lower temperature by as much as 200℃. The resulting pigment particles were in a micron range which is suitable for use in a ceramic glaze. The host structure (Mg2SiO4) could accommodate cobalt cations up to 20 at%. Investigation on the chemical distribution revealed that no chemical species from the flux reacted with pigment grains. Optical properties were examined by UV-vis spectroscopy and colorimetry. Technical performance of the obtained …
Tailoring Texture, Microstructure, And Shape Memory Behavior Of Niti Alloys Fabricated By L-Pbf-Am,
2021
University of Kentucky
Tailoring Texture, Microstructure, And Shape Memory Behavior Of Niti Alloys Fabricated By L-Pbf-Am, Sayed Ehsan Saghaian N.E.
Theses and Dissertations--Mechanical and Aerospace Engineering
Laser Powder Bed Fusion (L-PBF) is one of the most promising Additive Manufacturing (AM) methods to fabricate near net-shape metallic materials for a wide range of applications such as patient-specific medical devices, functionally graded materials, and complex structures. NiTi shape memory alloys (SMAs) are of great interest due to a combination of unique features, such as superelasticity, shape memory effect, high ductility, work output, corrosion resistance, and biocompatibility that could be employed in many applications in automotive, aerospace, and biomedical industries. Due to the difficulties with traditional machining and forming of NiTi components, the ability to fabricate complex parts, tailor …
Topological Design Of Pentamode Lattice Metamaterials Using A Ground Structure Method,
2021
Edith Cowan University
Topological Design Of Pentamode Lattice Metamaterials Using A Ground Structure Method, Zuyu Li, Zhen Luo, Lai-Chang Zhang, Chun-Hui Wang
Research outputs 2014 to 2021
Pentamode metamaterials are a new class of artificially engineering three-dimensional lattice composites. There exist a few types of pentamode metamaterials that are dominated by ad hoc design motifs, while a systematic design approach is still missing. This paper will present an efficient topological optimization methodology to discover a series of novel pentamode lattice microarchitectures over a range of effective material properties. Firstly, the necessary and sufficient condition that is required for elasticity constants of pentamode micro lattices with at least elastically orthotropic symmetry is derived. Secondly, a general mathematical formulation for design optimization of such pentamode micro lattices is developed. …
Advancement Of Full-Vector Variable-Temperature Magnetometry For Rock-Magnetic And Paleointensity Applications,
2021
Michigan Technological University
Advancement Of Full-Vector Variable-Temperature Magnetometry For Rock-Magnetic And Paleointensity Applications, Leonid Surovitskii
Dissertations, Master's Theses and Master's Reports
Data on the variation of the direction and strength of Earth’s ancient magnetic field (absolute paleointensity) provide crucial information into the mechanisms of the geodynamo and the Earth’s thermal history. However, the use of conventional methods and instrumentation for absolute paleointensity determination has been hampered by physicochemical alteration of the samples caused by multiple high-temperature cycles and long experiment durations. The reliability and efficiency of the measurement process can be improved by the measurement of the full remanent magnetization vector simultaneously with the temperature cycling of a sample. Such as approach can also substantially expand the scope of materials available …
On The Mechanical Properties Of Al/Cu-Grid/Al Intermetallic Composite,
2021
Chulalongkorn University
On The Mechanical Properties Of Al/Cu-Grid/Al Intermetallic Composite, Hamza Essoussi, Said Ettaqi
Journal of Metals, Materials and Minerals
The present paper deals with the experimental investigation of new process combining static compression with high temperature as a simple way to prepare new Al/Cu-grid/Al metallic composite (MC) that consists of Aluminum matrix and Copper grid acting as ductile reinforcement stacked between the Al sheets. At the stage of composite fabrication, two different thermal cycles were tested to highlight the effect of processing temperature on the layers’ adherence and the mechanical properties of the prepared composites. Consequently, the microstructural and mechanical results revealed that the compression at 630℃ for 30 min, then furnace cooled to 450℃ followed by air cooling …
Thermal Behavior Of Solid Acids In The Rb3h(So4)2-Rbhso4 System Under Ambient Atmosphere,
2021
Chulalongkorn University
Thermal Behavior Of Solid Acids In The Rb3h(So4)2-Rbhso4 System Under Ambient Atmosphere, Chatr Panithipongwut Kowalski, Permpoon Chaijaroen, Farook Kaewniyom
Journal of Metals, Materials and Minerals
The thermal behavior of solid acids in the Rb3H(SO4)2-RbHSO4 system under ambient atmosphere has been studied in comparison to the previously reported high-temperature behavior of the same system under humidified atmosphere. The findings showed that, under this level of humidity, the transition of RbHSO4, the transition of Rb5H3(SO4)4, and the disproportionation of Rb3H(SO4)2, occurred at the same temperatures as those under humidified atmosphere. However, the results from differential scanning calorimetry did not reveal the reaction temperature between Rb3H(SO4)2 and RbHSO4 due to the slow process. The dehydration temperatures of Rb5H3(SO4)4 were surprisingly similar between the systems under low and high …
