Engineering Commons^™

Engineering Order-Disorder Transitions For High-Performance Thermoelectric Fe2val Heusler Alloys, Cory T. Cline

Dartmouth College Ph.D Dissertations

Fe₂VAl shows great promise as an eco-friendly and low-cost replacement to conventional low-temperature (250-500 K) thermoelectric materials. Current thermoelectric materials use toxic and expensive elements like Te and Sb, whereas Fe₂VAl offers a larger power factor at a lower cost and a reduced risk of environmental pollution. The key issue with Fe₂VAl is the alloy’s relatively large thermal conductivity compared to its semiconductor competitors. This thesis aims to investigate a hierarchical approach to reduce lattice thermal conductivity through a preliminary exploration of heavy element substitutions and mechanical deformation, then through probing order-disorder transitions for …

Characterization Of Materials Properties In Additively Manufactured Aisi-420 Martensitic Steel Deposited By Laser Engineered Net Shaping, Md Mehadi Hassan

Nanoscience and Microsystems ETDs

Metal additive manufacturing (AM) is a disruptive technology enabling the fabrication of complex and near-net-shaped parts by adding material layer-wise. It offers reduced lead production time. AM processes are finding applications in many industrial sectors such as aerospace, automotive, biomedical, and mold tooling. Despite the tremendous advantages of AM, some challenges still prevent this technology's adoption in high-standard applications. Anisotropy and inhomogeneity in the mechanical properties of the as-built parts and the existence of pores and lack-of-fusion defects are considered the main issues in directed energy deposition (L-DED) parts. Laser-engineered net shaping LENS® offers excellent possibilities to fabricate metal tools …

An Overwiew On Corrosion Behavior Of Steels In Factory, H. Demiroren

Eurasian Journal of Physics and Functional Materials

In this study, corrosion behaviors of diffuser unit solutionbywhich raw sugar is produced from minced sugar beets in sugar factories on St-37 low alloy steel and AISI 304, 304L, 316 austenitic stainless steel types were examined. Moreover, influence of heat treatment on corrosion resistance was investigated. Corrosion tests were performed using mass loss method. SEM-EDX, X-rays Diffraction, microhardness and surface hardness analyses of samples were carried out. As a result, it was determined that AISI 304L and 316 steels have better corrosive resistance and heat treatment improves corrosion resistance.

Influence Of Parameters Of Non-Standard Modes Of Heat Treatment On Increasing The Wear Resistance Of Steel Products, Dorob Murotovich Berdiyev Dsn, Abdulaziz Abdullajanovich Yusupov Head Teacher, Ravshan Kobilovich Tashmatov Doctoral Student, Tuychi Nemat Ogli Ibodullayev Assistant, Kabira Erkinovna Qurbonova Head Teacher

Scientific-technical journal

The use of non-standard modes of heat treatment increases the density of dislocations in the crystal structure of the α-phase and increases the wear resistance of carbon, low-alloy steels under various friction conditions, which is comparable to the results when heated to a standard temperature (Ac₃+30÷50 °C). The preliminary extreme heating temperature is determined. After re-quenching at standard temperature and low tempering, the wear resistance of steels under various types of friction increases by up to 40 % compared to standard quenching.

Influence Of Parameters Of Non-Standard Modes Of Heat Treatment On Increasing The Wear Resistance Of Steel Products, Dorob Murotovich Berdiyev Dsn, Abdulaziz Abdullajanovich Yusupov Head Teacher, Ravshan Kobilovich Tashmatov Doctoral Student, Tuychi Nemat Ogli Ibodullayev Assistant, Kabira Erkinovna Qurbonova Head Teacher

Scientific-technical journal

The use of non-standard modes of heat treatment increases the density of dislocations in the crystal structure of the α-phase and increases the wear resistance of carbon, low-alloy steels under various friction conditions, which is comparable to the results when heated to a standard temperature (Ac₃+30÷50 °C). The preliminary extreme heating temperature is determined. After re-quenching at standard temperature and low tempering, the wear resistance of steels under various types of friction increases by up to 40 % compared to standard quenching.

Monolithic Chalcogenide Optical Nanocomposites Enable Infrared System Innovation: Gradient Refractive Index Optics, Myungkoo Kang, Laura Sisken, Charmayne Lonergan, Andrew Buff, Anupama Yadav, Claudia Goncalves, Cesar Blanco, Peter Wachtel, J. David Musgraves, Alexej V. Pogrebnyakov, Erwan Baleine, Clara Rivero-Baleine, Theresa S. Mayer, Carlo G. Pantano, Kathleen A. Richardson

Materials Science and Engineering Faculty Research & Creative Works

The size and weight of conventional imaging systems is defined by costly non-planar lenses and the complex lens assemblies required to minimize optical aberrations. The ability to engineer gradient refractive index (GRIN) optics has the potential to overcome constraints of traditional homogeneous lenses by reducing the number of components in optical systems. Here, an innovative strategy to realize this goal based on monolithic GRIN media created in Ge-As-Se-Pb chalcogenide infrared nanocomposites is presented. A gradient heat treatment to spatially modulate the volume fraction of high refractive index Pb-rich nanocrystals within a glass matrix is utilized, providing a GRIN profile while …

Research Of The Mechanical-Tribological Characteristics Of Ti3sic2/Tic Coatings After Annealing, D. B. Buitkenov, B. K. Rakhadilov, Zh. B. Sagdoldina, D. Erbolatuly, S. Amanzholov

Eurasian Journal of Physics and Functional Materials

This article investigates the influence of thermal annealing on microhardness and wear resistance of the surface of steel U9/Y9 protected by a composite coating Ti 3 SiC 2 /TiC obtained by detonation sputtering. Thermal annealing was performed in the range of temperatures 700-900 ◦ C during 1 hour. Following annealing the formation of TiO 2 and an increase in the phase content of Ti 3 SiC 2 are observed. Higher microhardness was obtained in coatings subjected to annealing at 800 ◦ C, which can be explained by an increase in the content of carbonized titanium. As the annealing temperature rises …

The Influence Of Heat Treatment On Corrosion Behavior Of Martensitic Stainless Steel Uns 42670, Armen Kvryan

Boise State University Theses and Dissertations

Ceaseless demand for lighter, faster, and more efficient aircraft has been one of the greatest driving forces behind bearing steel innovations. Recent studies demonstrate that corrosion is one of the leading causes of bearing failure in both military and commercial aircraft. High-performing bearing steels are available but are not being used in US military applications due to high cost and security issues when steels are produced outside of the continental United States. One approach to address this issue is to engineer steels that are cost-efficient and heat treated for corrosion resistance, long wear life, etc.

This dissertation presents information on …

A Study Of The Effect Of Heat Treatment On 3d Printed Pla Impact Strength, Suresh Thota

Electronic Theses and Dissertations

Environmental conditions have a significant effect on the mechanical properties of various materials. Environmental parameters such as temperature and humidity have a major impact on mechanical properties of materials such as compressive strength, tensile strength, bending strength and impact strength. The purpose of this research is to study how temperature and humidity affect the impact strength of 3D printed PLA plastic. Impact strength is the ability of a material to absorb energy subjected to an impact load by a pendulum. In this research, 3D printing was employed to produce PLA specimens which were later used for different experimental testings. For …

The Effects Of Atmospheric Heat Treatments On Tio2 Nanotube Anodes For Lithium-Ion Batteries, Andreas Savva

Boise State University Theses and Dissertations

The effects of various heat treatments on the physical and electrochemical properties of anatase TiO₂ nanotubes were studied in this work. Well-ordered TiO₂ nanotubes were grown via electrochemical anodization and annealed at 450°C to induce a phase transformation to anatase. The heat treatments were conducted under atmospheres of O₂, Ar, N₂, and water vapor (WV) to create different point defects. The oxygen-deficient atmospheres were used to generate oxygen vacancies in the TiO₂ nanotubes, while the water vapor treatment was used to create Ti vacancies by stabilizing them via the protonation of O sites. …

Analysis Of Optimal Process Conditions And Mechanical Properties On Nanocomposites According To Structural Changes Of Halloysite Nanotubes, Yun-Hae Kim, Soo-Jeong Park, Antonio Norio Nakagaito

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Effect Of Thermal Treatment On High Temperature Deformation Of Alloy Ep-~823, Martin Milburn Lewis

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this research topic is to determine mechanical properties of Alloy EP-823 and to provide a mechanistic understanding of its sensitivity to both thermal treatment and performance temperature. EP-823 is a leading target material for accelerator-driven waste transmutation applications. Overall, the tensile test results of Alloy EP-823 indicated a general trend of decreasing mechanical performance with an increase in tempering time. An increase in tempering time had a statistically significant inverse relationship with ultimate tensile strength (UTS) and yield strength (YS). An increase in tempering time did not have a significant effect on elongation and reduction in area. …

Effect Of Heat Treatment On The Mechanical Properties In Natural Bamboo, Austin Levy, Mackenzie Kirkpatrick

Materials Engineering

Previous studies have shown that heat treatments have the ability to improve mechanical strength and stiffness in hardwood species. Compared to structural hardwoods, bamboo is a more sustainable and globally viable renewable resource. Therefore, Bambusoides vivax (timber bamboo) culms were fabricated into flat, rectangular cross-section samples with varying cellulose content to be heat treated and tested for mechanical properties. All samples were heat treated (HT) twice. The first HT was a normalization of all samples at 103 +/- 3 °C. The second HT was performed at various times and temperatures ranging from 130°C to 170°C for 0.5 to 3 hours. …

Microstructure And Chemistry Evaluation Of Direct Metal Laser Sintered 15-5 Ph Stainless Steel, Kevin Coffy

Electronic Theses and Dissertations

15-5PH stainless steel is an important alloy in the aerospace, chemical, and nuclear industries for its high strength and corrosion resistance at high temperature. Thus, this material is a good candidate for processing development in the direct metal laser sintering (DMLS) branch of additive manufacturing. The chemistry and microstructure of this alloy processed via DMLS was compared to its conventionally cast counterpart through various heat treatments as part of a characterization effort. The investigation utilized optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray diffractometry (XRD), energy dispersive X-Ray spectroscopy (EDS) and glow discharge atomic emission spectrometry (GDS) …

A Case Study Of Heat Treatment On Aisi 1020 Steel, Sayed Shafayat Hossain, Md. Maksudul Islam, Md. Sajibul Alam Bhuyan

Md. Maksudul Islam

Proper heat treatment of steels is one of the most important factors in determining how they will perform in service. Engineering materials, mostly steel, are heat treated under controlled sequence of heating and cooling to alter their physical and mechanical properties to meet desired engineering applications. In this study we have chosen AISI 1020 steel as for our research work and we have tried to find out the mechanical properties (hardness) and micro structural properties (martensite formation, carbon self-locking region) by means of appropriate heat treatment process (annealing, normalizing & hardening). Here the steel specimens were heat treated in a …

Effect Of Heat Treatment On Phase Transformation Of Tio2 And Its Reflectance Properties, K Archaapinun, N Witit-Anun, P Visuttipitukul

Journal of Metals, Materials and Minerals

Titanium dioxide (TiO2) anti reflection coating film applied for solar cell application, gains more interest due to the insufficient energy problems today. Titanium dioxide can be found in several forms, and the most stable phase is rutile. This research aims to study effect of heat treatment on phase transformation of TiO2 and its effect on reflectance property. Titanium dioxide film was coated on silicon wafer by DC magnetron sputtering to obtain 190 nm and 420 nm thicknesses. Then, it was heat treated at 900C for 1 and 4 hours under ambient atmosphere. Phases and surface morphologies before and after heat …

Three-Body-Type Abrasive Wear Behavior Of 26% Cr Cast Iron With Molybdenum, A. Chooprajong, P. Sricharoenchai, S. Inthidech, Y. Matsubara

Journal of Metals, Materials and Minerals

Hypoeutectic 26 wt% Cr cast irons without and with Mo were prepared in order to investigate their abrasion wear resistance. The annealed specimens were hardened from 1323 K (As-H) and then tempered at three levels of temperatures between 673 and 823 K for 7.2ks, the temperature giving the maximum hardness (HTmax), lower temperature than that at HTmax (L-HTmax ) and higher temperature than that at HTmax (H-HTmax). The abrasive wear resistance was evaluated using Rubber Wheel abrasion test (three-body-type). It was found that hardness and volume fraction of retained austenite (V) in the heat-treated specimens varied with the Mo content …

The Effects Of Heat Treatment On Area Percent Porosity And Corrosion Behavior Of High-Nickel Thermal Spray Coatings, Travis Crowe, Alec Guraydin

Materials Engineering

Samples of two Thermal Spray Coating (TSC) alloys on a low carbon steel substrate were obtained: alloy C276 and Nicko-Shield 200. Specimens of each alloy were subjected to heat treatments at temperatures at 1100° for 60 minutes and 1200° for 10 minutes, with some specimens left in the as-sprayed condition. Three replicates were prepared for each condition. Thin 1” strips were cut using a diamond wafering blade for porosity measurements and 2” x 1” specimens were cut for corrosion testing using a SiC abrasive saw. The porosity specimens were mounted in acrylic resin, polished, and examined using SEM. From these …

Characterization Of The Relationship Between The Microstructure And Tensile Strength Of Annealed Ti-6al-4v, Aldo Corona

Materials Engineering

Tensile coupons of Ti-6Al-4V were heat treated at varying annealing temperatures from 1200°F (648°C) to 1450°F (787°C) at 50°F (23°C) increments for 1 hour. The samples were air cooled to room temperature or furnace cooled to 800°F (426°C) followed by air cooling to room temperature. Four tensile coupons were treated at each annealing temperature and cooling rate. Alpha case was observed to form on the surface of the samples post heat treatment with a maximum depth of 25 µm (.001 in). Samples were tensile tested for their ultimate tensile strength, yield strength, and percent elongation. Samples across all annealing temperatures …

An Investigation Of Microstructural Change Of Low Alloy Steel Aisi 4150 By Seebeck Coefficient, T Samran, P Termsuksawad

Journal of Metals, Materials and Minerals

Low alloyed steels, whose hardness can be modified by heat treatment, have been widely used in various applications. After heat treatment, they are normally destructively characterized and tested by many approaches via optical microscope and hardness testing. It is useful to develop a non-destructive method relating to its properties and microstructures. The proposed non-destructive approach in this study is the Seebeck coefficient measurement. The materials in this study were carbon steels AISI 4150 rod with a diameter of 1.3 cm and length of 3 cm. The specimens were heat-treated at 900ºC for 1 hour and were then cooled to room …

Effect Of K2o/Sio2 Ratio On The Crystallization Of Leucite In Silicate-Based Glasses, P Sooksaen, J Boonmee, C Witpathomwong, S Likhitlert

Journal of Metals, Materials and Minerals

Leucite-based glass-ceramics were prepared by controlled crystallization of suitable glass compositions to give required crystalline phase/s. Three glass batches in the system SiO2 - K2O - NaO2 - Al2O3 - TiO2 - CaO were prepared by varying K2O/SiO2 ratio, then melted and quenched. Glasses were characterized for onset of crystallization temperatures by differential thermal analysis (DTA), and heat treatments were carried out from 850 - 1000°C for 4 hours for controlled crystallization of leucite phase. Physical, chemical and crystal structure characterizations were carried out using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). XRD found …

The Effect Of Long-Term Thermal Exposure At Elevated Temperatures On Microstructures And Mechanical Properties In Centrifugally Casted Iron-Base Alloy, G Lothongkum, N Thaweepornkhasemsukh, P Wangyao

Journal of Metals, Materials and Minerals

This work has an aim to study and investigate the relationship between high temperature exposure conditions on microstructural evolution and mechanical properties in the iron-based alloy, Fe-30.8 Ni - 26.6 Cr alloy, strengthened by carbide precipitation. Two exposure temperatures (900 and 1000°C) with various thermal exposure times are introduced to the as-received alloy. After short-term exposure, it was found that the secondary carbides precipitated early near the primary carbides, which were chromium and niobium/titanium carbide networks. The secondary carbide precipitations were also found in the dendrite cores. The amounts of needle-like carbides and secondary carbide films increased with time and …

Structural And Diffusional Effects Of Hydrogen In Tini, Alan R. Pelton, Christine Trépanier, Xiao-Yan Gong, Andreas Wick, Katherine C. Chen

Materials Engineering

Hydrogen can be inadvertently added to Nitinol medical devices through electropolishing, caustic cleaning, or exposure to other acidic or basic solutions. Moderately high hydrogen concentrations can lead to embrittlement characterized by lowered ductility and changes in transformation behavior. The purpose of the present report is to discuss recent results on the effects of hydrogen in annealed TiNi. Samples are charged with hydrogen and analyzed with x-ray diffraction; these data indicate that even relatively small amounts of hydrogen can affect the crystal structure. Additions of up to 1000 wppm hydrogen increase the atomic volume by more than 2%, decrease peak intensity …

Effects Of 0.25 % Mo (Molybdenum) Which Is Contained In The Ductile Cast Iron On Mechanical Properties Of Austempered Ductile Iron (Adi)., Nukman Nukman, Bustanul Arifin, Bambang Sugiarto

Makara Journal of Technology

The aim of this research is to investigate the effects of 0.25 % Mo (Molybdenum) which is contained in the ductile cast iron on mechanical properties of Austempered Ductile Iron (ADI). The various temperatures and the holding times are used in the heat treatment processes. Using a given 0.25 % Mo in the ductile iron, ADI's alloyed developes a higher ultimate tensile stress value and decreases the elongation if we compare with the as cast (non alloy ductile iron). The higher impact energy value obtained at 9000 C austenization and 375o C austempering temperatures during 60 minutes holding times. The …