High-pressure torsion (HPT) is an effective severe plastic deformation (SPD)
technique to produce bulk nanostructured materials (BNMs). These BNMs often show a combination of exceptional mechanical and physical properties. Processing of single metals and alloys by HPT has been understood that the homogenous microstructures can be achieved throughout the disk...
The role of volumetric energy density on the microstructural evolution, texture and mechanical properties of 304L stainless steel parts additively manufactured via selective laser melting process is investigated. 304L is chosen because it is a potential candidate to be used as a matrix in a metal matrix composite with nanoparticles...
Water-atomized and gas-atomized 17-4 PH stainless steel powder were used as feedstock in selective laser melting process. Gas atomized powder revealed single martensitic phase after printing and heat treatment independent of energy density. As-printed water atomized powder contained dual martensitic and austenitic phase regardless of energy density. The H900 heat...
The fracture toughness is a critical material property that determines engineering performance.
However, as is well known for crystalline materials, if certain sample geometry and size
requirements are not met, test results become sample-size dependent and difficult to compare
among different studies. Here, the room-temperature fracture toughness of the Zr-based...
Full Text:
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[5] Ashby MF, Greer AL. Scr Mater 2006;54:321.
[6] Shek CH
Directed energy deposition and laser cladding technologies are suitable advanced manufacturing techniques for applying corrosion-resistant claddings to large carbon steel components. In this work, we clad 309L stainless steel wire onto carbon steel substrates and examine the effects of cladding parameters (laser power and travel speed) on metallurgical bonding, composition,...
Processing of metals through the application of high-pressure torsion (HPT) provides significant grain refinement in bulk metals at ambient temperatures. The ultrafine-grained (UFG) materials processed by HPT generally demonstrate the superior physical and mechanical characteristics. For utilizing the benefit of HPT, the feasibility of conventional HPT processing was demonstrated recently...
Amorphous metal thin films lack the grain boundaries and dislocations present in
crystalline metal films. As a result, amorphous metal films can be more mechanically robust, atomically smooth, and more resistant to chemical attack than crystalline metals. However, amorphous metals are meta-stable and subject to crystallization upon heating, thus limiting...
Vacuum arc remelting (VAR) is a secondary melting process for exotic alloys. The main purpose of this process is to increase the input ingot’s physical and chemical homogeneity. This is accomplished through the application of a high current that melts the material through the emergence of electrical arcs that induce...
The behavior of a metal vapor plasma arc in a vacuum arc remelting (VAR) furnace is believed to contribute to the formation of defects in reactive metal and super-alloy ingots. Industry standard instrumentation, which includes electric current and voltage measurements, can asses the stability of an arc but cannot predict...
The overall objective of this dissertation study was to develop and validate the performance of cellulose nanomaterials (CNs) incorporated fruit coatings for improving the storability of postharvest pears and bananas under various storage conditions. Four specific studies were conducted to fulfill the research objectives as stated below.
First, cellulose nanocrystal...
Most of the concrete in the world is produced using hydraulic cement (ordinary portland cement, OPC) and siliceous or alumino-siliceous supplementary cementitious materials (SCM). Due to the shift in focus toward environmental sustainability within the construction industry, alkali-activated cementitious systems (AAC) have gained significant attention to reduce the carbon footprint...
The motivation for undertaking this research was to increase the understanding of processing colloidal semiconductor nanocrystals and thin films metallic glasses to enable their wider application in future devices. This research covered two unique materials, lead selenide (PbSe) nanocrystals and thin film metallic glass alloy of zirconium copper aluminum nickel...
The influence of shear rate and temperature on the viscosity and fragility of the Zr₄₁.₂Ti₁₃.₈Cu₁₂.₅Ni₁₀.₀Be₂₂.₅ (Vit1) metallic glass forming liquid is measured in the liquid and undercooled liquid state between 907 and 1300 K. The results show a complex rheological behavior of Vit1. The viscosity of Vit1 is about three...
Idaho National Laboratories recently conducted micromechanical testing of nano-recrystallized UO₂ as a part of an ongoing investigation of High Burnup Structure (HBS). The goals of the test were to determine the fracture stress, and the elastic modulus of subdivided grains within UO₂ using ion irradiation rather than neutron irradiation to...
This study investigates what leads managers to allocate constrained cognitive effort toward new versus familiar aspects of a business. Specifically, we explore advice giving by venture capital firms (VCs) to their portfolio companies, distinguishing between business topics on which a VC has advised other ventures in the past and topics...
Smart Manufacturing (SM) is envisioned to make manufacturing processes more efficient through automation and integration of networked information systems. Robotic arms are integral to this vision. However the benefits of SM, enabled by automation and networking, also come with cyber risks.
In this work, we propose an anomaly detection framework...
This study examined four occupational health risks that contribute to job strain, the experience of infectious disease, musculoskeletal strain, job dissatisfaction, and depressive symptoms, for toddler teachers as predictors of classroom quality. Both the physical and social settings of early care and education (ECE) are influential in shaping children’s early...
The Advanced Test Reactor (ATR) is conducting
scoping studies for the conversion of its fuel from a
highly enriched uranium (HEU) composition to a low-enriched
uranium (LEU) composition, through the
Reduced Enrichment for Research and Test Reactors
Program, within the Global Threat Reduction Initiative.
These studies have considered a wide...