Metallurgy Commons^™

Cold-Formed Steel Strength Predictions For Combined Bending And Torsion, Yu Xia, Robert S. Glauz, Benjamin W. Schafer, Michael Seek, Hannah B. Blum

Engineering Technology Faculty Publications

Locally slender cross-section members, such as cold-formed steel Cee and Zee sections, are susceptible to significant twisting and high warping torsion stresses. Torsion considerations are complicated by whether it is derived as a first-order effect from loading or a second-order effect from instability. The current design for combined bending and torsion interaction has some limitations, including only considering the first yield in torsion and ignoring the cross-section slenderness in torsion. Previous work has derived a simple uniform equation to predict the bimoment capacity and two bimoment strength curves for local and distortional buckling under torsion only. This work is extended …

Residual Stress Distribution, Distortion, And Crack Initiation In Conventional And Intensive Quench Practices, Kingsley Tochukwu Amatanweze, Mario F. Buchely, Viraj Ashok Athavale, Laura Bartlett, Ronald J. O'Malley, Toshi Suzuki

Materials Science and Engineering Faculty Research & Creative Works

This study evaluates the effect of two different quench practices on distortion, sensitivity to quench cracking, development and distribution of residual stress, microstructural uniformity, and hardenability of standardized test castings. Navy C-rings made of AISI 4340 were quenched in this experiment. Some rings were quenched in a conventional draft tube immersion quench bath, and others were quenched in an intensive quench spray system to compare with the results from the conventional immersion quench bath. The rings were measured with a coordinate measuring machine, for distortion and flatness, before and after quenching. Hardness profiles of the quenched rings showed through hardness …

Compositional Modifications To Alter And Suppress Laves Phases In Alxcrmotayti Alloys, Austin E. Mann, Joseph William Newkirk

Materials Science and Engineering Faculty Research & Creative Works

Herein, the Development of Refractory Complex Concentrated Alloys in the Al–Cr–Mo–Ta–Ti Alloy System is Reported. Alloys with Modified Al and Ta Concentrations Are Designed using CALPHAD Tools and Produced Via Arc Melting and Characterized in Both As-Cast and Annealed Forms. Properties of the Alloys, Nature of the Microstructures, and Phase Transformation Behavior Are Described Via X-Ray Diffraction, Microstructural Characterization, Microhardness, and Differential Scanning Calorimetry. Two Alloys, Namely, Al0.25CrMoTa0.8Ti and Al0.75CrMoTa0.8Ti, Are Represented by a Body-Centered-Cubic Matrix Phase after Annealing, along with a Secondary Cr–Ta Laves Phase of the C15 and C14 Polytypes, respectively. in As-Cast and Annealed Forms, the Al0.75CrMoTa0.45Ti …

Characterization Of Virgin, Re-Used, And Oxygen-Reduced Copper Powders Processed By The Plasma Spheroidization Process, M. Hossein Sehhat, David Perez-Palomino, Connor Wiedemeier, Tristan Cullom, Joseph William Newkirk

Materials Science and Engineering Faculty Research & Creative Works

Fabrication of parts with high mechanical properties heavily depend on the quality of powder deployed in the fabrication process. Copper powder in three different powder types were spheroidized using radio-frequency inductively coupled plasma (ICP) spheroidization process (TekSphero-15 system). The characterized powders include virgin powder as purchased from the powder manufacturer, powder used in electron beam powder bed fusion (EB-PBF) process, and reconditioned powder, which was used powder that underwent an oxygen-reduction treatment. The goal of spheroidizing these powder types was to evaluate the change in powder morphology, the possibility of enhancing the powder properties back to their as-received conditions, and …

Characterization Of Virgin, Re-Used, And Oxygen-Reduced Copper Powders Processed By The Plasma Spheroidization Process, M. Hossein Sehhat, David Perez-Palomino, Connor Wiedemeier, Tristan Cullom, Joseph William Newkirk

Mathematics and Statistics Faculty Research & Creative Works

Fabrication of parts with high mechanical properties heavily depend on the quality of powder deployed in the fabrication process. Copper powder in three different powder types were spheroidized using radio-frequency inductively coupled plasma (ICP) spheroidization process (TekSphero-15 system). The characterized powders include virgin powder as purchased from the powder manufacturer, powder used in electron beam powder bed fusion (EB-PBF) process, and reconditioned powder, which was used powder that underwent an oxygen-reduction treatment. The goal of spheroidizing these powder types was to evaluate the change in powder morphology, the possibility of enhancing the powder properties back to their as-received conditions, and …

Effect Of Sc On Recrystallization Resistance Of Aa7050, Keaton Schmidt

Dissertations, Master's Theses and Master's Reports

The extrusion process involves high temperatures and strains that can result in undesirable microstructures, especially along the surface. Extruded alloys tend to exhibit surface recrystallization during heat treating at regions of higher strains, which can lead to reduced fatigue strength and corrosion resistance. By adding Sc to AA7050, nano-sized dispersoids are formed with Sc cores and Zr shells that restrict recrystallization more than the base alloy that only utilizes Zr. Billets with varying Sc content and a control with only Zr were cast, and extrusions were made in order to compare surface microstructures at varying strains in the as-extruded and …

Optimizing The Extrudability Of 6082 Aluminum By Varying The Magnesium And Silicon Concentration, Eli A. Harma

Dissertations, Master's Theses and Master's Reports

Alloy 6082 aluminum is used for high-volume manufacturing in the automotive industry due to its high strength, impact performance, and corrosion resistance. However, given these improved properties, the alloy has decreased formability compared to other 6xxx series alloys, especially in the extrusion process. Controlling the dynamic recovery and recrystallization properties by changing the additions of Mg and Si can improve the hot deformation properties. Five alloys of varying Mg and Si concentrations between 0.6 to 1.2wt% Mg and 0.7 to 1.3wt% Si were made with constant concentrations of Cr, Fe, and Mn and the same homogenization heat treatment. The proposed …

Recycling Metal Chips Into Usable Materials, Alex Mortensen, Ben Mortensen

Williams Honors College, Honors Research Projects

This report entails the scope, design considerations, and plans for creating a metal chip converter into metal briquettes. The construction is a set of machines with multiple processes to make the conversion happen. The process includes washing fine metal chips, drying them off, compressing them, and melting them down into usable briquettes. This project is intended to make a simple process to recycle metal chips into usable material for reuse. The project's objective is to reduce the costs of storage and recycling waste by offering a solution to recycle it into materials the shop can reuse.

An Updated Analytical Method For Predicting The Bracing Behavior Of Z-Purlin Supported Standing Seam Diaphragm Systems, Michael W. Seek

Engineering Technology Faculty Publications

Roof systems utilizing Z-purlins as a secondary member supporting a standing seam panel system are used extensively by the metal building industry. The Z-purlins rely on the diaphragm action in the standing seam panel system to provide lateral support and transfer forces to anchorages. The behavior of the standing seam system is highly nonlinear making prediction of the interaction between the Z-purlin and the standing seam system difficult. To better understand the behavior of the interaction between the purlins and the panel system, a series of non-linear shell finite element models were developed based on the test results of simple …

Investigation Of Microstructurally Dependent Mechanical Properties Of Cold Sprayed Copper Using Correlative Microscopy, Quintin Otto

UNF Graduate Theses and Dissertations

This project employs multi-instrument materials characterization to analyze material made with the “Cold Spray” additive manufacturing process. Cold spray is an emerging additive manufacturing technique with unique benefits resulting from its low temperature adhesion process induced by plastic deformation. Metallic powder collides at high speeds creating three dimensional materials and coatings without the need for melting. Copper cold sprayed specimens were analyzed using a series of imaging techniques to characterize the microstructure at varying levels of detail and magnification. Scanning electron microscopy and electron back scattered diffraction were paired with microhardness testing to generate a correlative comparison between microstructure and …

Application Of Multi-Scale Computational Techniques To Complex Materials Systems, Mujan N. Seif

Theses and Dissertations--Chemical and Materials Engineering

The applications of computational materials science are ever-increasing, connecting fields far beyond traditional subfields in materials science. This dissertation demonstrates the broad scope of multi-scale computational techniques by investigating multiple unrelated complex material systems, namely scandate thermionic cathodes and the metallic foam component of micrometeoroid and orbital debris (MMOD) shielding. Sc-containing "scandate" cathodes have been widely reported to exhibit superior properties compared to previous thermionic cathodes; however, knowledge of their precise operating mechanism remains elusive. Here, quantum mechanical calculations were utilized to map the phase space of stable, highly-faceted and chemically-complex W nanoparticles, accounting for both finite temperature and chemical …

การศึกษาการดูดซับไอออนเงินและทองแดงด้วยผงจากใบว่านหางจระเข้, พิชญา อัครานุรักษ์กุล

Chulalongkorn University Theses and Dissertations (Chula ETD)

ด้วยสมบัติทางกายภาพของใบว่านหางจระเข้ ที่มีลักษณะเป็นรูพรุน ใบว่านหางจระเข้จึงมีความโดดเด่นและมีโอกาสพัฒนาขึ้นเป็นผงดูดซับสำหรับใช้ในกระบวนการกำจัดโลหะประเภทต่างๆ ในงานวิจัยนี้ได้ทำการศึกษาเกี่ยวกับการกำจัดไอออนเงินและไอออนทองแดงโดยใช้ผงจากใบว่านหางจระเข้ สายพันธ์บาร์บาเดนซิส (Barbadensis) เป็นตัวดูดซับ โดยมีการเตรียมผงด้วยกระบวนการอบให้ใบว่านหางจระเข้แห้งจากนั้นนำไปบดด้วยเครื่องบดละเอียด ตัวแปรการศึกษาประสิทธิภาพการดูดซับประกอบด้วย ปริมาณของตัวดูดซับ (0.2-1.0 กรัม) ค่าความเข้มข้นเริ่มต้นของสารละลายไอออนทองแดงและสารละลายไอออนเงิน (15-50 มิลลิกรัมต่อลิตร) ค่า pH (2-7) รวมทั้งศึกษาไอโซเทอมและแบบจำลองจลนพลศาสตร์ของการดูดซับเพื่อความเข้าใจในกลไกของการดูดซับของผงใบว่านหางจระเข้ ภาพถ่ายจากกล้องจุลทรรศน์อิเล็กตรอนแสดงให้เห็นว่าผงว่านหางจระเข้มีลักษณะเป็นรูพรุนระดับไมโครเมตร ผลการทดสอบการดูดซับโลหะ ได้แสดงให้เห็นว่าผงของใบว่านหางจระเข้ที่เตรียมขึ้น มีประสิทธิภาพในการดูดซับเงินในสารละลายไอออนเงินสูง เงื่อนไขที่เหมาะสมที่สุดในการดูดซับสารละลายไอออนเงินที่ความเข้มข้นเริ่มต้น 20 มิลลิกรัมต่อลิตร คือปริมาณตัวดูดซับ 0.2 กรัม ค่า pH 7 ซึ่งมีประสิทธิภาพการดูดซับถึงร้อยละ 95.6 ส่วนผลการทดสอบการดูดซับโลหะทองแดงความเข้มข้นเริ่มต้น 20 มิลลิกรัมต่อลิตร ที่มีประสิทธิภาพสูงสุดใช้ปริมาณตัวดูดซับ 1.0 กรัม ค่า pH 5 ซึ่งมีประสิทธิภาพการดูดซับร้อยละ 65.7 จลนพลศาสตร์ของการดูดซับทั้งในไอออนโลหะทองแดงและไอออนโลหะเงินอธิบายได้ด้วยสมการ pseudo second-order และลักษณะของการดูดซับที่เกิดขึ้นอยู่บนไอโซเทอมแบบแลงเมียร์ งานวิจัยนี้สามารถสรุปได้ว่า ผงจากใบว่านหางจระเข้มีโอกาสในการต่อยอดการพัฒนาเพื่อนำไปใช้ในการดูดซับโลหะจากสารละลายต่างๆ อาทิ ดูดซับโลหะในน้ำยาล้างบริเวณบ่อชุบเพื่อลดความเข้มข้นของโลหะก่อนปล่อยทิ้ง เป็นต้น

การป้องกันการเกิดออกไซด์ของโลหะดีบุกผสมบิสมัท 1% โดยน้ำหนัก, ภควัต พลมณี

Chulalongkorn University Theses and Dissertations (Chula ETD)

การเกิดฟิล์มออกไซด์ในดีบุกผสมบิสมัท 1% โดยน้ำหนักบนแผ่นขัดเงาจากปรากฎการณ์ออกซิเดชัน ทำให้ประสิทธิภาพของผงขัดบนแผ่นขัดเงาลดลง เพื่อให้ทราบถึงอัตราการเกิดออกซิเดชันในสภาวะที่ถูกจำกัดปัจจัยการเกิดฟิล์มออกไซด์คือ ออกซิเจนในรูปแบบต่าง ๆ เช่น ความชื้นในอากาศเป็นต้น จึงได้ทำการหาอัตราการเกิดออกไซด์ที่เกิดขึ้นโดยเทคนิคทางเคมีไฟฟ้า และทำการหาชนิดของฟิล์มที่เกิดขึ้นด้วยเทคนิคโฟโตอิเล็กตรอนสเปกโตสโกปี ปัจจัยที่ส่งผลในการเกิดออกซิเดชันที่ได้ศึกษาในงานวิจัยชิ้นนี้คือ เวลา และสิ่งแวดล้อมที่จำกัดออกซิเจนที่อุณหภูมิห้อง ผลของการทดสอบออกซิเดชันมีดังนี้ ในบรรยากาศปกติความชื้น 28%-35% พบการเกิดออกซิเดชันที่เป็นไปตามกฎของพาราโบลาที่มีสมาการคือ x = 8.7041t0.14 โดยที่ x คือความหนาของฟิล์มและ t คือเวลาที่ใช้ทดสอบออกซิเดชัน ในบรรยากาศแก๊สอาร์กอน, สุญญากาศ, บิวเทน และที่ห่อด้วยพลาสติก ไม่ได้ถูกจำกัดด้วยกฎพาราโบลา และมีแนวโน้มที่ฟิล์มจะมีความหนาน้อยกว่า แต่ต้องการเวลาในการทำการทดสอบมากกว่านี้เพื่อให้ได้ผลและแนวโน้มอัตราที่ชัดเจน ในการวิเคราะห์ผลจากเทคนิคโฟโตอิเล็กตรอนสเปกโตสโกปีในชิ้นงานที่ผ่านการทำออกซิเดชันในสุญญากาศและที่จัดเก็บด้วยการห่อพลาสติก พบว่าทั้งสองชิ้นงานโดยรวมแล้วมีชนิดของฟิล์มออกไซด์เป็นแบบเดียวกัน โดยจะประกอบไปด้วยไอออนของสารประกอบ SnO, SnO2, Sn(OH)2 และ Sn(OH)4 ซึ่งจากผลการทดลอง จะได้แบบจำลองของชั้นฟิล์มออกมาเป็นชั้น ๆ คือ ชั้นที่ 1 เป็นผิวนอกสุดมีออกไซด์ SnO2 และ Sn(OH)4 อยู่เป็นกลุ่มก้อนไม่สม่ำเสมอ (คลัสเตอร์) ชั้นที่ 2 เป็น SnO และ Sn(OH)2 ชั้นที่ 3 เป็น SnO2 และ Sn(OH)4

Elastoplastic Quasi-Static And Impact Load Response Of Steel Structure Sub-Assemblage With Cfrp Strips, Ali Al Aloosi, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

Presented in this paper is the outcome of an experimental investigation of the elastoplastic quasi-static and impact load response of a steel sub-assemblage constructed using a pair of hollow square section members with or without Carbon Fiber Reinforced Polymer (CFRP) strips. The sub-assemblage consists of a long structural member welded to a short member, thus representing a typical combination of a column and a beam on the face of a multi-story steel building frame. The column is subjected to a lateral quasi-static or impact load. Tests are conducted on four separate steel sub-assemblages. The first two tests are conducted with …

Design And Fabrication Of A High-Performance Heat Exchanger Using An Optimized Three-Dimensional Surface Structure Through Additive Manufacturing, Seth T. Waters

College of Graduate Studies: Theses & Dissertations

A heat exchanger is a device used to transfer thermal energy between two intertwining fluid pathways. In this study, the design of a novel heat exchanger is proposed using functional gradient double gyroid structure. The complex internal geometries of the gyroid structure significantly increases the surface area to volume ratio, and potentially could expressively improve efficiency of the heat transfer. The proposed idea provides a new approach for the design of a high-efficiency heat exchanger. In order to fabricate the complex structured heat exchanger system additive manufacturing is adapted instead of traditionally subtractive manufacturing techniques or casting. The prototypes of …

Cascaded Sapphire Fiber Bragg Gratings Inscribed By Femtosecond Laser For Molten Steel Studies, Dinesh Reddy Alla, Deva Prasad Neelakandan, Farhan Mumtaz, Rex E. Gerald, Laura Bartlett, Ronald J. O'Malley, Jeffrey D. Smith, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

This research reports a distributed fiber optic high-temperature sensing system tailored for applications in the steel industry and various other sectors. Recent advancements in optical sensor technology have led to the exploration of sapphire crystal fibers as a solution for sensing in harsh environments. Utilizing a femtosecond (fs) laser, cascaded fiber Bragg gratings (FBGs) were meticulously fabricated within a multimode sapphire optical fiber. These FBGs endowed the system with distributed sensing capabilities and underwent rigorous testing under extreme temperatures, reaching up to 1,800 °C. The study delves into the investigation of the FBG reflection spectrum, facilitated by the development of …

Characterization Of Virgin, Re-Used, And Oxygen-Reduced Copper Powders Processed By The Plasma Spheroidization Process, M. Hossein Sehhat, David Perez-Palomino, Connor Wiedemeier, Tristan Cullom, Joseph William Newkirk

Materials Science and Engineering Faculty Research & Creative Works

Fabrication of parts with high mechanical properties heavily depend on the quality of powder deployed in the fabrication process. Copper powder in three different powder types were spheroidized using radio-frequency inductively coupled plasma (ICP) spheroidization process (TekSphero-15 system). The characterized powders include virgin powder as purchased from the powder manufacturer, powder used in electron beam powder bed fusion (EB-PBF) process, and reconditioned powder, which was used powder that underwent an oxygen-reduction treatment. The goal of spheroidizing these powder types was to evaluate the change in powder morphology, the possibility of enhancing the powder properties back to their as-received conditions, and …

Suppressing Aluminum/Silica Exchange Reaction Between High Aluminum Steel And Mold Flux During Continuous Casting Process, Kuanysh Nurbekuly Yermukhanbetov

Masters Theses

"Mold flux plays one of the critical roles in continuous casting of steel. It performs five primary functions: thermal and chemical insulation, lubrication between the steel strand and mold, absorption of inclusions, and promotion of even heat flux. The aluminum/silica exchange reaction occurring between steel and mold flux during the continuous casting process poses significant challenges in the steel industry. This reaction can lead to various defects in the cast product and adversely affect its surface quality, as well as downstream processing.

In this work, effectiveness of two approaches, namely slag dopant additions and electrochemical techniques, in suppressing the exchange …

Investigation Of Oxidation And Corrosion Resistance Of Ni-Based Alloys And Stainless Steels Under Co2 Environments At Elevated Temperatures, Spencer Roy Fultineer

Graduate Theses, Dissertations, and Problem Reports (ETD)

High mechanical strength integrity, high robustness towards oxidation, and high resistance to carburization under CO2 environments at elevated temperatures are usually required for metallic systems that are employed for power generation. INCONEL 625 is a nickel-based superalloy that started development in the 1950s. This material was designed with the distinct purpose of use in high-temperature and high-pressure systems. While various materials possess the physical properties to handle these conditions, the creation of IN625 addresses the need for a material to withstand the highly corrosive properties of these kinds of environments. In order to evaluate the oxidation and corrosion resistance of …

Damage Stability Study Of A 500 Dw Ro-Ro Ferry Vessel, Zulfaidah Ariany, Budhi Santoso, Sarwoko Sarwoko, Nauval Abdurrahman Prasetyo

Makara Journal of Technology

The development of the crossing transportation industry is currently increasing in the island areas. The use of Ro-Ro type ferry boats is extremely efficient in moving people, goods, and vehicles. The current research focuses on the damage stability of the 500 DWT Ro-Ro ferry, which aims to meet the needs of the Ro-Ro ferry in the archipelago area. The previously existing initial design of a barge hull with a main size Lpp = 40.15 m, B = 12 m, H = 3.2 m, and T = 2.15 m was used to analyze the damage stability condition further. First, the drawings …