Metallurgy Commons^™

The Comparison Of Dixon–Mood And 1/Nf Methods For Fatigue Limit Estimation Of 17–4 Ph Stainless Steel (H900), Arthur Pallar Pallar

Masters Theses

This study compares two methods for estimating the fatigue limit of 17-4 PH stainless steel (H900): the Dixon–Mood staircase and Kujawski 1/Nf linear method. Tests were conducted on an MTS Acumen 3 kN system under axial tension–tension loading at R = 0.1 and 50 Hz, following the standard practice defined in ASTM E466-15. Flat specimens were fabricated by water-jet cutting and polished. Tensile tests verified mechanical properties consistent with published data for the H900 condition. Fifteen specimens tested by the staircase method yielded a mean fatigue limit of 1138 MPa. The 1/Nf analysis using four specimens produced 1159 MPa, 2 …

Measurement And Process Relation For Cast Surface Defects, Nachiket Laxman Shinde

Masters Theses

This thesis presents an in-depth investigation into the classification and prediction of surface defects in aluminum sand castings using a combination of experimental trials and machine learning techniques. Key process variables such head height, pouring temperature, resin %, sand type and process were systematically varied to study their influence on defects like veining, and burn-on. Comparative analysis indicated superior performance of the deep learning model in handling nonlinear interactions between process parameters. The study emphasizes the importance of integrating data-driven models with foundry practices to enhance surface quality, reduce rework, and support intelligent decision-making in casting operations.

Ni-Mn-In Heusler Alloy Ribbon For Magnetocaloric Application, Bao Nguyen

Masters Theses

A traditional cooling system, which applies compression technology within the working fluid, has had a lot of negative impacts on the environment and has low efficiency. They have almost reached the thermodynamic efficiency; there is little room for further improvement. Therefore, solid-state cooling systems, especially those that use the magnetocaloric effect (MCE), have drawnmuch interest as an alternative solution for the vapor-compression system. The Heusler alloy, especially Ni-Mn-In in this research, can be an excellent candidate for this application due to its unique properties, such as the shape memory effect and giant MCE. Their giant MCE results from a first-order …

Data-Driven Decision Making For Quality Control In Foundry Applications, Ronit Shetty

Dissertations

In the transformative landscape of Industry 4.0, advanced quality control in manufacturing demands innovative methods for processing and analyzing datasets. This dissertation presents a comprehensive study on leveraging high volume data and machine learning to enhance decision making in the foundry industry. The research explores three crucial challenges in the foundry industry: predicting surface roughness, monitoring refractory coating thicknesses, and comparing feature extraction techniques for surface quality classification. The findings underscore the transformative potential of integrating advanced feature engineering techniques and machine learning into manufacturing quality control.

The first of the three challenges introduces a framework that integrates digital images …

Segregation And Heat Treatment Response Of Cast Quench And Partition Steels, Mujeeb Hussain Shaik

Masters Theses

Quench and partition (Q&P) steels have emerged as promising alternatives to traditional quenching and tempering methods, offering a superior balance of strength and ductility due to their unique microstructure of martensite, and retained austenite. This literature review examines the development and optimization of Q&P steels, focusing on their mechanical properties, heat treatment processes, and applications in various industries. This study explores the application and effectiveness of the Quench and Partition (Q&P) heat treatment process on cast steels and examines segregation phenomena in cast medium Mn steels. Medium Mn steels were employed for various Q&P cycles on cast specimens to investigate …

Analysis Of The Cyclic Behavior And Fatigue Damage Of Low Alloy Steels, Zahra Salemi Najafabadi

Dissertations

Fatigue is the most common type of failure in many structures and components subjected to cyclic loading. Surface effects in fatigued materials are of particular importance, since in most cases the surface is the preferred site of fatigue crack initiation. Microcracks originate at the metal surface due to stress concentration introduced by macro notches and micro defects in the surface layers. The microcrack initiation and propagation are controlled by the localized plastic deformation in the surface layers especially in the initial stage of fatigue failure process. Therefore, the knowledge regarding the cyclically induced changes in deformation resistance at the metal …

Martensitic And Inter-Martensitic Transformations In Magnetocaloric Ni2.15mn0.85ga Heusler Alloy, A. Madiligama, P. Ari-Gur, Y, Ren, V, Shavrov, Y. Ge, J. George, I. Musabirov, V. Koledov

Mechanical and Aerospace Engineering Faculty Publications

The entropy changes of successive martensitic phase transformations in Ni-Mn-Ga Heusler alloys can be utilized to realize enhanced magnetocaloric properties. A detailed study of phase transformations of one such alloy, Ni2.15Mn0.85Ga, (ΔQ = 4900 J/kg at 343 K, under 140 kOe), is reported here. Upon cooling, the paramagnetic cubic (L21) austenitic phase transforms into a ferromagnetic 7M modulated monoclinic martensitic phase. This phase is stable in a narrow temperature range, and upon further cooling, transforms into a non-modulated ferromagnetic tetragonal (L10) phase. The separation between the equilibrium temperatures of the austenitic and tetragonal martensitic phases is only ~50 K. The …

An Investigation On Formability And Crystallographic Texture In Novel Magnesium Alloys, Pnina Ari-Gur, Andreas Quojo Quainoo, Shubram Subramanyam, Ashkan Razania, Sven Vogel, Wei Gao

Mechanical and Aerospace Engineering Faculty Publications

Magnesium alloys offer many advantages. They offer very low density and good strength. They also offer good damping properties. One of the industries where reducing component weight is the automotive industry. That makes the magnesium alloys good candidates for these applications. Reduced weight of an automobile means also lower fuel consumption. The hexagonal closed packed structure of magnesium, lends itself to strong mechanical anisotropy. In the current work, neutron diffraction was used to study the crystallographic texture developed in novel magnesium alloys during cold rolling operations. The texture was compared with that developed in the commercial AZ-31 magnesium alloy. Tests …

A Multiscale Thermomechanical Metal Additive Manufacturing Simulation And The Impact Of Geometry On Residual Stress And Distortion, Luis Fernando Silva Velasco

Masters Theses

Metal additive manufacturing is an enabling technology for the rapid prototyping and manufacturing of geometrically complex parts that would otherwise be difficult or impossible to manufacture. However, the manufacturing process can produce undesired residual stresses and distortions. The first part of the work describes the implementation of a multiscale, thermo-mechanical simulation modeling the metal powder bed fusion additive manufacturing process. NASA’s Micromechanics Analysis Code was is to incorporate the microscale effects of an evolving material porosity on the predicted macroscale residual fields. The simulation shows that modeling an evolving material porosity, as the material transitions from a metal powder to …

Texture And Residual Stresses On Nanocomposite Coatings, Hussam E. Aikhasawneh

Masters Theses

Nickel was electroplated on cold-rolled 2024-T3 aluminum. The coating was done with reinforcement by nanoparticles of y-alumina or silicon carbide. For comparison, nickel-only coatings were done too. Rectangular samples were coated in nickel sulfamate bath with no particles to determine the optimum coating conditions. The optimized parameters were the current density, time of coating, and agitation rate. After coating conditions were established, composite samples were coated using these conditions. The coated layer was characterized by measuring: thickness, residual stresses, and crystallographic preferred orientation. The coated layer was tested by SEM for evaluation of the quality of the coatings. The presence …