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Dynamic Precipitation of Second Phase Under Deformed Condition in Mg-nd Based Alloy

Description: Magnesium alloys are the lightweight structural materials with high strength to weigh ratio that permits their application in fuel economy sensitive automobile industries. Among the several flavors of of Mg-alloys, precipitation hardenable Mg-rare earth (RE) based alloys have shown good potential due to their favorable creep resistance within a wide window of operating temperatures ranging from 150°C to 300°C. A key aspect of Mg-RE alloys is the presence of precipitate phases that leads to str… more
Date: December 2013
Creator: Dendge, Nilesh Bajirao
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Influence of ordered L1₂ precipitation on strain-rate dependent mechanical behavior in a eutectic high entropy alloy

Description: This article focuses on Al0.7CoCrFeNi, a lamellar dual-phase (fcc + B2) precipitation-strengthenable eutectic high entropy alloy. The back-stresses from the coherent L12 precipitate were insufficient to cause improvement in twin nucleation, owing to elevated twinning stress under quasi-static testing. However, under dynamic testing high density of twins were observed.
Date: April 23, 2019
Creator: Gwalani, Bharat; Gangireddy, Sindhura; Zheng, Yufeng; Soni, V.; Mishra, Rajiv & Banerjee, Rajarshi
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Titanium Boride Formation and Its Subsequent Influence on Morphology and Crystallography of Alpha Precipitates in Titanium Alloys

Description: Over the last two decades there has been an increased interest in understanding the influence of trace boron additions in Ti alloys. These additions refine the prior β grain size in as-cast Ti alloys along with increasing their modulus and yield strength due to the precipitation of TiB. TiB also acts as a heterogeneous nucleation site for α precipitation and has been shown to influence the α phase morphology. B is completely soluble in liquid Ti but has a negligible solubility in both body cent… more
Date: December 2013
Creator: Nandwana, Peeyush
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Next Generation Friction Stir Welding Tools for High Temperature Materials

Description: The historical success of friction stir welding (FSW) on materials such as aluminum and magnesium alloys is associated with the absence of melting and solidification during the solid-state process. However, commercial adoption of FSW on steels and other non-ferrous high-strength, high-temperature materials such as nickel-base and titanium-base alloys is limited due to the high costs associated with the process. In this dissertation, the feasibility of using an FSW approach to fabricate certain … more
This item is restricted from view until August 1, 2028.
Date: July 2023
Creator: Gaddam, Supreeth
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Thermo-mechanical response of single-phase face-centered-cubic AlxCoCrFeNi high-entropy alloy microcrystals

Description: Article describes the response of [100]-oriented single-crystal face-centered-cubic Al0.1CoCrFeNi and Al0.3CoCrFeNi high-entropy alloy (HEA) microcrystals tested from 293 to 573 K by means of in situ micro-compression.
Date: March 13, 2018
Creator: Jiao, Quan; Sim, Gi-Dong; Komarasamy, Mageshwari; Mishra, Rajiv; Liaw, Peter K. & El-Awady, Jaafar A.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Evaluation of intermetallic compound layer at aluminum/steel interface joined by friction stir scribe technology

Description: Article describes the results of friction stir welding of aluminum and steel, in which heat input and high strain rate deformation during resulted in the diffusion-based formation of a FexAly intermetallic compound (IMC) layer.
Date: April 12, 2019
Creator: Wang, Tianhao; Sidhar, Harpreet; Mishra, Rajiv; Hovanski, Yuri; Upadhyay, Piyush & Carlson, Blair
Item Type: Refine your search to only Article
Partner: University of North Texas
open access

Effect of Microstructure on the Deformation Mechanism of Friction Stir-Processed A₁₀.₁CoCrFeNi High Entropy Alloy

Description: This article reports grain refinement using friction stir processing and a detailed study on the microstructural evolution at various locations in the processed region using scanning electron microscopy, in addition to the effect of grain refinement on the tensile properties and the underlying deformation mechanisms in both coarse-grained and fine-grained materials.
Date: September 15, 2014
Creator: Komarasamy, Mageshwari; Kumar, N.; Tang, Z.; Mishra, Rajiv & Liaw, P.K.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Additive friction stir deposition: a deformation processing route to metal additive manufacturing

Description: This article outlines key advantages of additive friction stir deposition, e.g. rendering fully-dense material in the as-printed state with fine, equiaxed microstructures, identifies its niche engineering uses, and points out future research needs in process physics and materials innovation.
Date: November 24, 2020
Creator: Yu, Hang Z. & Mishra, Rajiv
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Achieving extraordinary structural efficiency in a wrought magnesium rare earth alloy

Description: Article describes development of an ultrafine-grained magnesium alloy with an extraordinary strength and ductility combination, exceptional high specific strength, zero yield strength asymmetry and excellent high strain rate superplasticity.
Date: January 29, 2020
Creator: Panigrahi, S. K.; Mishra, Rajiv; Brennan, R.C. & Cho, K. C.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Work hardening in metastable high entropy alloys: a modified five-parameter model

Description: Article models work hardening response in TRIP HEAs under tensile deformation, which reflects the hardening due to synergistic activity of multiple deformation mechanisms, using a five-parameter work hardening model.
Date: April 19, 2022
Creator: Haridas, Ravi Sankar; Agrawal, Priyanka; Yadav, Surekha; Agrawal, Priyanshi; Gumaste, Anurag & Mishra, Rajiv
Item Type: Refine your search to only Article
Partner: UNT College of Engineering

Small Scale Fracture Mechanisms in Alloys with Varying Microstructural Complexity

Description: Small-scale fracture behavior of four model alloy systems were investigated in the order of increasing microstructural complexity, namely: (i) a Ni-based Bulk Metallic Glass (Ni-BMG) with an isotropic amorphous microstructure; (ii) a single-phase high entropy alloy, HfTaTiVZr, with body centered cubic (BCC) microstructure; (iii) a dual-phase high entropy alloy, AlCoCrFeNi2.1, with eutectic FCC (L12) -BCC (B2) microstructure; and (iv) a Medium-Mn steel with hierarchical microstructure. The micro… more
This item is restricted from view until August 1, 2025.
Date: July 2023
Creator: Jha, Shristy
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Dynamic Shear Deformation of a Precipitation Hardened Al0.7CoCrFeNi Eutectic High-Entropy Alloy Using Hat-Shaped Specimen Geometry

Description: The article reports on the shear deformation of a eutectic structured HEA and effect of precipitation on shear deformation, particularly Al₀.₇CoCrFeNi high-entropy alloy (HEA). A split-Hopkinson pressure bar (SHPB) was used to compress the hat-shaped specimens to study the local dynamic shear response of the alloy. The change in the width of shear bands with respect to precipitation and deformation rates was studied. The precipitation of L1₂ phase did not delay the formation of adiabatic shear… more
Date: April 10, 2020
Creator: Gwalani, Bharat; Wang, Tianhao; Jagetia, Abhinav; Gangireddy, Sindhura; Muskeri, Saideep; Mukherjee, Sundeep et al.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Design approaches for printability-performance synergy in Al alloys for laser-powder bed additive manufacturing

Description: This article highlights that design of Al alloys for laser-powder bed fusion (L-PBF) can lead to fundamental change in the microstructure evolution, proposed alloy design strategies lead to synergy between and printability and performance, hierarchical and heterogeneous microstructures have potential to overcome the strength-ductility tradeoff, and alloy design incorporating the specific attributes of an AM technology is crucial to maximizing its potential.
Date: March 10, 2021
Creator: Mishra, Rajiv & Thapliyal, Saket
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

High-Throughput Investigation of Multiscale Deformation Mechanism in Additively Manufactured Ni Superalloy

Description: Article discusses how, in this paper, Inconel 718 (IN718) superalloy was processed by laser powder-bed fusion additive manufacturing (L-PBFAM), followed by heat treatment. Evidence of extensive deformation of twin networks and dislocation cells was revealed by transmission electron microscopy of the deformed region under the nanoindentation tip.
Date: February 17, 2023
Creator: Dhal, Abhijeet; Agrawal, Priyanka; Haridas, Ravi Sankar; Gaddam, Supreeth; Sharma, Aishani; Parganitha, Digvijay et al.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Friction stir-based additive manufacturing

Description: This article is a review of friction stir additive manufacturing (FSAM) and additive friction stir deposition (AFSD) and provides a systems approach framework and a conceptual process model to guide researchers.
Date: January 18, 2022
Creator: Mishra, Rajiv; Haridas, Ravi Sankar & Agrawal, Priyanshi
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

On the evolving nature of c/a ratio in a hexagonal close-packed epsilon martensite phase in transformative high entropy alloys

Description: Article studying c/a ratio and transformation volume change of h.c.p. (hexagonal close packed) epsilon martensite phase in transformative high entropy alloys (HEAs) quantified as functions of alloy chemistry, friction stir processing and tensile deformation. The study reveals that while intrinsic c/a is dependent on alloying elements, c/a of epsilon in transformative HEAs changes with processing and deformation.
Date: September 12, 2019
Creator: Sinha, Subhasis; Nene, Saurabh S.; Frank, Michael; Liu, Kaimiao; Agrawal, Priyanka & Mishra, Rajiv
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

A novel nano-particle strengthened titanium alloy with exceptional specific strength

Description: This article microstructurally tailors an exceptionally high-strength titanium alloy, Ti-6Al-2Sn-4Zr-6Mo (Ti6246) through friction stir processing (FSP) in order to provide enhanced weight savings and improved fuel efficiency. The specific strength attained in one of the conditions is close to 450 MPa m³/mg, which is about 22% to 85% greater than any commercially available metallic material. This novel nano particle strengthened Ti alloy is a potential replacement for many structural alloys, en… more
Date: August 13, 2019
Creator: Dutt, Aniket K.; Gwalani, Bharat; Tungala, Vedavyas; Carl, Matthew; Mishra, Rajiv; Tamirisakandala, Sesh A. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Impact of Processing Parameters and Forces on Channels Created by Friction Stir Bobbin Tools

Description: In this thesis, friction stir channeling (FSC) and its process parameters influence on geometry, surface quality and productivity are explored. The probe of the friction stir processing (FSP) tool used to perform these tests was a modified submerged bobbin tool made of MP 159 Co-Ni alloy. The body was made from H13 tool steel. To find the optimal channel conditions for a targeted range of process parameters, multiple 6061 aluminum samples were prepared with a U shape guide to test the effects … more
Date: May 2022
Creator: Koonce, James G
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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