Mechanical Engineering Commons^™

Study On The Thermal Distortion, Hardness, And Microstructure Of St 37 Steel Plate Joined Using Fcaw, Maijuansyah Maijuansyah, Yanuar Rohmat Aji Pradana, Gaguk Jatisukamto, Solichin Solichin

Journal of Mechanical Engineering Science and Technology (JMEST)

This study sets out to investigate the distortion angle, microstructure, and hardness of St 37 steel plate weld joint produced by FCAW using the welding current of 80, 110, and 140 A. By using flat position, CO2 and E71T-1 wire were utilized as a shielding gas and electrode filler, respectively. The distortion angle measurement was done on 3 different locations of the welded sample perpendicular to weld direction by using bevel protractor. The micro Vickers tests were then applied gradually at the crosssectional surface with a distance of 0, 5, 10 and 15 mm from weld centerline using the load …

Investigation Of Through Thickness Microstructure And Mechanical Properties In Friction Stir Welded 7n01 Aluminum Alloy Plate, Xingxin Zhao, Zhiyong Yang, Joseph P. Domblesky, Jianmin Han, Zhiqiang Li, Xiaolong Liu

Mechanical Engineering Faculty Research and Publications

An on-going problem in friction stir welded (FSW) joints used in the high-speed train sector is that the microstructure and mechanical properties can significantly vary in thick sections. Because inhomogeneous properties can reduce weld efficiency and degrade service performance, it is of some interest to understand how inhomogeneous properties can develop in FSW welds made from precipitation hardening alloys such as 7N01. In the current study, butt welds were made using 12 mm thick plates and then sectioned perpendicular to the weld line. Five 2.2 mm thick slices were cut from a section and used to measure tensile properties access …

A Study On Ultrasonic Energy Assisted Metal Processing : Its Correeltion With Microstructure And Properties, And Its Application To Additive Manufacturing., Anagh Deshpande

Electronic Theses and Dissertations

Additive manufacturing or 3d printing is the process of constructing a 3-dimensional object layer-by-layer. This additive approach to manufacturing has enabled fabrication of complex components directly from a computer model (or a CAD model). The process has now matured from its earlier version of being a rapid prototyping tool to a technology that can fabricate service-ready components. Development of low-cost polymer additive manufacturing printers enabled by open source Fused Deposition Modeling (FDM) printers and printers of other technologies like SLA and binder jetting has made polymer additive manufacturing accessible and affordable. But the metal additive manufacturing technologies are still expensive …

Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu

Mechanical & Aerospace Engineering Theses & Dissertations

The off-axis compressive behavior of ice-templated ceramic was analyzed using experimental results and micro-mechanical model simulation. Ice-templated ceramics is a versatile processing technique used to manufacture anisotropic ceramic foam by exploiting the anisotropic growth characteristics and lamellar morphology. The ice-templating process results in processing-structure-property relationships determined by the microstructure. The processed alumina samples which were later manufactured by water jet machine from the freeze casting were tested under quasi-static off-axis loading conditions and were used to determine the mechanical properties of the material. Digital image correlation (DIC) was used to measure the strain response of ice-templated ceramic under off-axis loading. …

Effect Of Diffusion Distance On Evolution Of Kirkendall Pores In Titanium-Coated Nickel Wires, Aaron R. Yosta, Dinc Erdeniz, Ashley E. Paz Y Puente, David C. Dunanda

Mechanical Engineering Faculty Research and Publications

Microtubes of near-equiatomic nickel-titanium (NiTi) alloys can be created via the Kirkendall effect during NiTi interdiffusion, when nickel wires are surface-coated with titanium via pack cementation and subsequently homogenized. This study explores the effect of diffusion distance upon Kirkendall microtube formation in NiTi by considering a range of Ni wire diameters. For Ni wire diameters of 25, 50 and 100 μm, titanized at 925 °C for 0.5, 2, and 8 h to achieve average NiTi composition, partial interdiffusion occurs concurrently with Ti surface deposition, resulting in concentric shells of NiTi₂, NiTi and Ni₃Ti around a Ni …

Process-Property-Microstructure Relationships In Laser-Powder Bed Fusion Of 420 Stainless Steel., Subrata Deb Nath

Electronic Theses and Dissertations

Laser-powder bed fusion (L-PBF) is an additive manufacturing technique for fabricating metal components with complex design and customized features. However, only a limited number of materials have been widely studied using L-PBF. AISI 420 stainless steel, an alloy with a useful combination of high strength, hardness, and corrosion resistance, is an example of one such material where few L-PBF investigations have emerged to date. In this dissertation, L-PBF experiments were conducted using 420 stainless steel powders to understand the effects of chemical composition, particle size distribution and processing parameters on ensuing physical, mechanical and corrosion properties and microstructure in comparison …

Microstructures And Hardness Of Tig Welded Experimental 57fe15cr25ni Steel, Parikin Parikin, Mohammad Dani, Abu Khalid Rivai, Agus Hadi Ismoyo, Riza Iskandar, Arbi Dimyati

Makara Journal of Technology

The microstructures and hardness of tungsten inert gas (TIG) welded experimental 57Fe15Cr25Ni steel were investigated through optical–scanning electron microscopy analyses and with a hardness tester, respectively. The welding process restructured the constituent atoms into regular and irregular crystal lattices. Rapid cooling of the weld metal allowed the formation of a dendritic (columnar) structure, with porous grains. By contrast, slow cooling influenced HAZ and led to the formation of grain structures. The crystal lattice became more organized and larger than other zones. Meanwhile, the base metal formed circular nets that covered large area inside thick and thin grain boundaries. The diffraction …

Material-Process-Property Relationships Of 17-4 Stainless Steel Fabricated By Laser-Powder Bed Fusion Followed By Hot Isostatic Pressing., Harish Irrinki

Electronic Theses and Dissertations

17-4 PH stainless steel is commonly used in medical, tooling, automotive, chemical and aerospace industries due to its excellent strength and corrosion properties. Additive manufacturing processes such as laser-powder bed fusion (L-PBF) have gained attention and importance due to the potential to produce complex-shaped three-dimensional parts for various industries. In order to manufacture three-dimensional components from 17-4 PH stainless steel powder using L-PBF, it is critical for design and manufacturing engineers to have an awareness of various material options and corresponding processing and post-processing conditions to obtain useful mechanical properties from the process. The goal of this dissertation is to …

The Effect Of Rotational Speed, Friction Duration, And Pressure On Tensile Strength Of Aisi 6061 Welding Joints, Dewi Puspitasari, Poppy Puspitasari, M. Rizka Gita Firmansyah, Solichin Solichin

Journal of Mechanical Engineering Science and Technology (JMEST)

Electric arc welding with covered electrodes is ideally suited for flat plates. If this technique is employed for welding rigid bodies, the results would be of poor quality. One viable solution to weld rigid bodies is through friction welding. The study aimed to investigate the tensile strength of specimens subjected to friction welding with variations in rotational speed, friction time, and pressure and to examine the microstructure of friction welding joints. This research used the one-shot case study design and involved descriptive analysis. The descriptive analysis described the results of tensile testing and microstructure of welding joints. Results showed that …

Direct Metal Laser-Sintered Stainless Steel: Comparison Of Microstructure And Hardness Between Different Planes, M. Ghasri-Khouzani, H. Peng, R. Attardo, P. Ostiguy, J. Neidig, R. Billo, D. Hoelzle, M. R. Shankar

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microstructural analysis and micro-hardness measurements were performed on different planes of 316L stainless steel fabricated by direct metal laser sintering (DMLS) technique. A fine cellular network was observed within the steel microstructure, where morphology of most cells changed from columnar on XZ-plane (vertical section) to equiaxed on XY-plane (horizontal section). Correspondingly, morphology of most grains was found to alter from columnar for the XZ-plane to equiaxed in the case of the XY-plane. Moreover, X-ray diffraction (XRD) analysis revealed a fully austenitic structure for both the planes. The average micro-hardness value for the XZ-plane and XY-plane was insignificantly (≈ 3%) different, …

An Integrated Microstructural-Nanomechanical-Chemical Approach To Examine Material-Specific Characteristics Of Cementitious Interphase Regions, Mahdieh Khedmati, Yong-Rak Kim, Joseph A. Turner, Hani Alanazi, Charles Nguyen

Department of Mechanical and Materials Engineering: Faculty Publications

Effective properties and structural performance of cementitious mixtures are substantially governed by the quality of the interphase region because it acts as a bridge transferring forces between aggregates and a binding matrix and is generally susceptible to damage. As alternative binding agents like alkali-activated precursors have obtained substantial attention in recent years, there is a growing need for fundamental knowledge to uncover interphase formation mechanisms. In this paper, two different types of binding materials, i.e., fly ash-based geopolymer and ordinary portland cement, were mixed with limestone aggregate to examine and compare the microstructures and nanomechanical properties of interphase region. To …

An Integrated Microstructural-Nanomechanical-Chemical Approach To Examine Material-Specific Characteristics Of Cementitious Interphase Regions, Mahdieh Khedmati, Yong-Rak Kim, Joesph A. Turner, Hani Alanazi, Charles Nguyen

Department of Mechanical and Materials Engineering: Faculty Publications

Effective properties and structural performance of cementitious mixtures are substantially governed by the quality of the interphase region because it acts as a bridge transferring forces between aggregates and a binding matrix and is generally susceptible to damage. As alternative binding agents like alkali-activated precursors have obtained substantial attention in recent years, there is a growing need for fundamental knowledge to uncover interphase formation mechanisms. In this paper, two different types of binding materials, i.e., fly ash-based geopolymer and ordinary portland cement, were mixed with limestone aggregate to examine and compare the microstructures and nanomechanical properties of interphase region. To …

Investigation Of Microstructure And Mechanical Properties By Direct Metal Deposition, Jingwei Zhang

Doctoral Dissertations

"Microstructure and properties of Direct Metal Deposition (DMD) parts are very crucial to meeting industrial requirements of parts quality. Prediction, and control of microstructure and mechanical properties have attracted much attention during conventional metal manufacturing process under different conditions. However, there is few investigations focused on microstructure simulation and mechanical properties control under different process parameters during DMD process. This dissertation is intended to develop a multiscale model to investigate Ti6Al4V grain structure development and explore Ti6Al4V based functionally graded material (FGM) deposit properties during DMD process. The first research topic is to investigate and develop a cellular automaton-finite element …

Microstructural Evaluation Of Hydrogen Embrittlement And Successive Recovery In Advanced High Strength Steel, Quentin Scott Allen

Theses and Dissertations

Advanced high strength steels (AHSS) have high susceptibility to hydrogen embrittlement, and are often exposed to hydrogen environments in processing. In order to study the embrittlement and recovery of steel, tensile tests were conducted on two different types of AHSS over time after hydrogen charging. Concentration measurements and hydrogen microprinting were carried out at the same time steps to visualize the hydrogen behavior during recovery. The diffusible hydrogen concentration was found to decay exponentially, and equations were found for the two types of steel. Hydrogen concentration decay rates were calculated to be -0.355 /hr in TBF steel, and -0.225 /hr …

Multiple Scattering Theory For Polycrystalline Materials With Strong Grain Anisotropy: Theoretical Fundamentals And Applications, Huijing He

Department of Mechanical and Materials Engineering: Faculty Publications

This work is a natural extension of the author’s previous work: “Multiple scattering theory for heterogeneous elastic continua with strong property fluctuation: theoretical fundamentals and applications” (arXiv:1706.09137 [physics.geo-ph]), which established the foundation for developing multiple scattering model for heterogeneous elastic continua with either weak or strong fluctuations in mass density and elastic stiffness. Polycrystalline material is another type of heterogeneous materials that widely exists in nature and extensively used in industry. In this work, the corresponding multiple scattering theory for polycrystalline materials with randomly oriented anisotropic crystallites is developed. To validate the theory, the theoretical results for a series of …

Microstructure Correlation With Formability For Biaxial Stretching Of Magnesium Alloy Az31b At Mildly Elevated Temperatures, David T. Fullwood, Isaac Chelladurai, Michael P. Miles, John E. Carsley, Raj K. Mishra, Irene J. Beyerlein, Marko Knezevic

Faculty Publications

Magnesium AZ31B sheets of 2 mm thickness were stretch formed using a 101.6 mm diameter punch at temperatures from 25°C - 150°C, in 25°C increments. Surface strains were measured using a digital image correlation (DIC) method. The punch height vs load curve was found to be the same for temperatures of 25°C and for 50°C, while at 75°C and above the load for a given punch height started to decrease, indicating a potential change in deformation mechanism. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the tested specimens. In particular, the gradual decrease in twinning …

Effects Of Microstructure On The Strain Rate Sensitivity Of Advanced Steels, Rakan Alturk, Steven Mates, Zeren Xu, Fadi Abu-Farha

Publications

The dependence of the strain rate sensitivity of advanced ~1 GPa tensile strength steels on the phases present in their microstructures was studied by testing different steels at 0.005 and 500 s−¹. The high strain rate tests were performed using a Kolsky bar setup, while the quasi-static tests were performed using a universal testing machine. The two main steels of interest were the Ferrite-Martensite DP980 and the Ferrite-Martensite-Austenite QP980; the latter being a transformation induced plasticity (TRIP) assisted steel. For comparison, ferritic CR5 mild steel and austenitic stainless steel 201 were also tested under the same conditions. Though …

Shape Memory Behavior Of Dense And Porous Niti Alloys Fabricated By Selective Laser Melting, Soheil Saedi

Theses and Dissertations--Mechanical and Aerospace Engineering

Selective Laser Melting (SLM) of Additive Manufacturing is an attractive fabrication method that employs CAD data to selectively melt the metal powder layer by layer via a laser beam and produce a 3D part. This method not only opens a new window in overcoming traditional NiTi fabrication problems but also for producing porous or complex shaped structures. The combination of SLM fabrication advantages with the unique properties of NiTi alloys, such as shape memory effect, superelasticity, high ductility, work output, corrosion, biocompatibility, etc. makes SLM NiTi alloys extremely promising for numerous applications.

The SLM process parameters such as laser power, …

Micro/Nanostructures Formation By Femtosecond Laser Surface Processing On Amorphous And Polycrystalline Ni60nb40, Edwin Peng, Alfred Tsubaki, Craig A. Zuhlke, Meiyu Wang, Ryan Bell, Michael J. Lucis, Troy P. Anderson, Dennis R. Alexander, George Gogos, Jeffrey E. Shield

Department of Mechanical and Materials Engineering: Faculty Publications

Femtosecond laser surface processing is a technology that can be used to functionalize many surfaces, imparting specialized properties such as increased broadband optical absorption or superhydrophilicity/superhydrophobicity. In this study, two unique classes of surface structures, below surface growth (BSG) and above surface growth (ASG) mounds, were formed by femtosecond laser surface processing on amorphous and polycrystalline Ni₆₀Nb₄₀ with two different grain sizes. Cross sectional imaging of these mounds revealed thermal evidence of the unique formation processes for each class of surface structure. BSG mounds formed on all three substrates using the same laser parameters had similar surface …

Processing, Microstructure, And Mechanical Properties Of Zirconium Diboride-Molybdenum Disilicide Ceramics And Dual Composite Architectures, Ryan Joseph Grohsmeyer

Doctoral Dissertations

"This research had two objectives: characterization of processing-microstructure-mechanical property relationships of conventional ZrB₂-MoSi₂ ceramics at room temperature (RT) and 1500⁰C in air, and fabrication of ZrB₂-MoSi₂ dual composite architectures (DCAs) for use near 1500⁰C. Elastic moduli, fracture toughness, and flexure strength were measured at RT and 1500⁰C for 15 ZrB₂-MoSi₂ ceramics hot pressed using fine, medium, or coarse ZrB₂ starting powder with 5-70 vol.% MoSi₂, referred to as FX, MX, and CX respectively where X is the nominal MoSi₂ content. MoSi₂ decomposed during sintering, resulting in …

Study On The Impact Abrasive Wear Of New Super-High Manganese Steel, Wenyan Wang

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

No abstract provided.

Simulation Of Two Kinds Of Hot Stamping Processes Of Ultra High-Strength Steel, Hao Zhao, Zhongwen Xing, Hongliang Yang

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

No abstract provided.

Void Closure And The Sensitivity Analysis Of The Process Parameters During Forging Of Large Steel Ingot, Bo Jiang, Yazheng Liu, Jianlin Sun, Guanglei Liu, Zhilin Wang, Zhigang Zhao

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

No abstract provided.

Weld Thermal Simulation Of Crmov With Pwht In Type Iv Region, Bin Xu

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

No abstract provided.

Flow Stress And Microstructure Models Of Alloys, Lars-Erik Lindgren

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

No abstract provided.

Secondary Electron Emission From Plasma Processed Accelerating Cavity Grade Niobium, Miloš Bašović

Mechanical & Aerospace Engineering Theses & Dissertations

Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier.

Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for higher …

The Effects Of Thermal Procedure On Transformation Temperature, Crystal Structure And Microstructure Of Cu-Al-Co Shape Memory Alloy, Y. Aydoğdu, M. Kök, F. Dağdelen, A. Aydoğdu, Ali S. Turabi, Haluk E. Karaca

Mechanical Engineering Faculty Publications

The purpose of this study is to investigate the effects of different thermal procedures of the Cu-Al-Co shape memory alloy on its crystal structure, transformation temperature and microstructure. The alloys were subjected to a heat treatment and then cooling was applied at four different conditions. After the thermal process, XRD, DSC, optical microscopy and micro-hardness measurements were carried out. The experimental studies showed that crystal structure, microstructure and transformation temperature of Cu-Al-Co alloy were changed from the cooling conditions.

Cryogenic Processing Of Al 7050-T7451 Alloy For Improved Surface Integrity, Bo Huang

Theses and Dissertations--Mechanical and Aerospace Engineering

Al 7050-T7451 alloy with good combinations of strength, stress corrosion cracking resistance and toughness, is used broadly in the aerospace/aviation industry for fatigue-critical airframe structural components. However, it is also considered as a highly anisotropic alloy as the crack growth behavior along the short transverse direction is very different from the one in the long transverse direction, due to the inhomogeneous microstructure with the elongated grains distributed in the work material used in the sheet/plate applications. Further processes on these materials are needed to improve its mechanical and material properties and broaden its applications.

The material with ultra-fine or nano …

An Adapted Approach To Process Mapping Across Alloy Systems And Additive Manufacturing Processes, Luke Charles Sheridan

Browse all Theses and Dissertations

The continually growing market for metal components fabricated using additive manufacturing (AM) processes has called for a greater understanding of the effects of process variables on the melt pool geometry and microstructure in manufactured components for various alloy systems. Process Mapping is a general approach that traces the influence of process parameters to thermal behavior and feature development during AM processing. Previous work has focused mainly on Ti-6Al-4V (Ti64), but this work uses novel mathematical derivations and adapted process mapping methodologies to construct new geometric, thermal, and microstructural process maps for Ti64 and two nickel superalloy material systems. This work …

Elucidating The Role Of Microstructure, Texture, And Microtexture On The Dwell Fatigue Response Of Ti-6al-4v, Alec Mitchell Blankenship

Browse all Theses and Dissertations

Ambient temperature dwell sensitivity is known to be deleterious to the fatigue response of near-alpha titanium alloys. Dwell fatigue refers to the presence of a sustained hold at peak stress as opposed to the continuous variation of normal cyclic fatigue loading. This reduction in failure life-times from dwell loading is attributed to early crack nucleation and faster crack propagation. The degradation is the result of plastic anisotropy on the microstructural scale along with tendency of titanium alloys to creep at low temperatures at stresses well below the 0.2% offset yield strength. Despite being the most widely used titanium alloy, Ti-6Al-4V …