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in creator/contributor: "Wright, J.L."

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Stability of ultrafine lamellar structures during aging in two-phase {gamma}-TiAl alloys

Two-phase {gamma}-tail alloys such as PM Ti-47Al-2Cr-2Nb or Ti-47Al- 2Cr-1Nb-Ta hot extruded above the {alpha}-transus temperature have unique refined-colony/ultrafine lamellar structures. These lamellar microstructures consist of very fine laths of the {gamma} and {alpha}{sub 2} phases, with average interlamellar spacings of 100 nm and {alpha}{sub 2}-{alpha}{sub 2} spacings of 200 nm, and are dominated by {gamma}/{alpha}{sub 2} interfaces. This ultrafine lamellar structure remains stable durin… more

Date: August 1, 1997

Creator: Maziasz, P. J.; Liu, C. T. & Wright, J. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fracture in Bulk Amorphous Alloys

The fracture behavior of a Zr-based bulk amorphous alloy, Zr-10 AI-5 Ti-17.9 Cu-14.6 Ni, was examined by transmission electron microscopy (TEM) and x-ray diffraction for any evidence of crystallization preceding crack propagation. No evidence for crystallization was found in shear bands in compression specimens or at the fracture surface in tensile specimens. In- situ TEM deformation experiments were performed to more closely examine actual crack tip regions. During the in-situ deformation expe… more

Date: November 30, 1998

Creator: Horton, J. A. & Wright, J. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fracture toughness of commercial hard magnets

In some demanding magnetic applications such as electric vehicle drive motors in which high rpm and small air gaps are necessary, the Nd{sub 2}Fe{sub 14}B magnets need to be used as a structural element. Any improvement in their fracture resistance will reduce the failure rates during commercial use. For current uses, an improvement in the toughness would allow greater machinability and easier handling. As a prelude to a program to improve the fracture toughness of Nd{sub 2}Fe{sub 14}B magnets,… more

Date: April 1, 1996

Creator: Horton, J. A.; Wright, J. L. & Herchenroeder, J. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Key microstructures controlling the mechanical properties of two-phase TiAl alloys with lamellar structures

TiAl alloys with the base composition of Ti-47Al-2Cr-2Nb (at.%) were prepared by arc melting and drop casting, followed by hot extrusion above the {alpha}-transus temperature, T{sub {alpha}}. The hot extruded materials were then heat treated above and below T{sub {alpha}} in order to control microstructural features in these lamellar structures. Mechanical properties of these alloys were determined by tensile testing at temperatures to 1000 C. Tensile elongation at room temperature (RT) is stro… more

Date: December 31, 1996

Creator: Liu, C. T.; Maziasz, P. J. & Wright, J. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Processing and properties of molybdenum silicide intermetallics containing boron

Molybdenum-silicon-boron intermetallics with the composition Mo-10.5 Si-1.1 B, wt% (Mo-26.7 Si-7.3 B, at. %) were fabricated by several processing techniques. Powder processing (PM) resulted in macrocrack-free material containing no or only few microcracks. The PM materials contained quasi-equilibrium pores and large concentrations of oxygen. Average room temperature flexure strengths of 270 MPa were obtained. At 1,200 C in air, flexure strengths as high as 600 MPa were observed. These high val… more

Date: August 1, 1997

Creator: Schneibel, J.H.; Liu, C.T.; Heatherly, L.; Wright, J.L. & Carmichael, C.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Multi-Phase Cr-Based Alloys for Aggressive High Temperature Environments

The objective of this work is to develop and characterize a new family of Cr-based alloys for structural use in aggressive 900-1300 C corrosion environments. The potential advantages of Cr are high melting point, moderate density, and good high-temperature corrosion resistance in many environments [1]. However, these are currently negated by inadequate high-temperature strength, ambient-temperature brittleness, and susceptibility to environmental embrittlement at elevated-temperatures by rapid … more

Date: April 22, 2003

Creator: Brady, M.:.; Liu, C.T.; Tortorelli, P.F.; Sachenko, P.; Walker, L.R.; Carmichael, C.A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ultrahigh temperature intermetallic alloys

A new family of Cr-Cr{sub 2}Ta intermetallic alloys based on Cr-(6--10)Ta (at.%) is under development for structural use in oxidizing environments in the 1,000-1,300 C (1,832--2,372 F) temperature range. Development objectives relate to high temperature strength and oxidation resistance and room temperature fracture toughness. The 1,200 C (2,192 F) strength goals have been met: yield and fracture strengths of 275 MPa (40 ksi) and 345 MPa (50 ksi), respectively, were achieved. Progress in attain… more

Date: November 1, 1998

Creator: Brady, M. P.; Zhu, J. H.; Liu, C. T.; Tortorelli, P. F.; Wright, J. L. & Carmichael, C. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Concept of Operations for Data Fusion Visualization

Situational awareness in the operations and supervision of a industrial system means that decision making entity, whether machine or human, have the important data presented in a timely manner. An optimal presentation of information such that the operator has the best opportunity accurately interpret and react to anomalies due to system degradation, failures or adversaries. Anticipated problems are a matter for system design; however, the paper will focus on concepts for situational awareness e… more

Date: September 1, 2011

Creator: McJunkin, T. R.; Boring, R. L.; McQueen, M. A.; Shunn, L. P.; Wright, J. L.; Gertman, D. I. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Cr{sub 2}Nb-based alloy development

Two-phase Cr-Cr{sub 2}Nb alloys (designated as CN alloys) were prepared by arc melting, followed by directional solidification, HIPping, or hot extrusion at 1450 to 1500C. The microstructure of CN alloys containing 6 to 12 at.% Nb depended strongly on alloying additions, heat treatment, and material processing. Tensile properties were sensitive to defects. Hot extrusion at 1480C was most effective in reducing as-cast defects and refining the cast Cr-Cr{sub 2}Nb eutectic structure and thus impro… more

Date: July 1, 1995

Creator: Liu, C. T.; Tortorelli, P. F.; Horton, J. A.; Easton, D. S.; Schneibel, J. H.; Heatherly, L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department