Transmission electron microscopy of rapidly solidified micron-size carbide powders of titanium and zirconium

1983 ◽  
Vol 41 ◽  
pp. 68-69
Author(s):  
C. S. Pande ◽  
S. Smith
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rapid Solidification ◽  
Basic Mechanism ◽  
Transport Processes ◽  
Loss Analysis ◽  
Transmission Electron ◽  
Micron Size ◽  
Potential Benefits ◽  
Rapidly Solidified

It is well known that rapid solidification in materials may result in unique microstructure and properties. These novel features are determined largely by the transport processes occurring at the liquid/solid interface. However, a detailed study of the basic mechanism of rapid solidification and its correlation with resultant chemistry and microstructure is needed to fully utilize the potential benefits of rapid solidification processing. We have used transmission electron microscopy, and related techniques such as energy dispersive x-ray analysis in thin films and electron energy loss analysis for this study. The material chosen for this purpose was rapidly solidified very fine carbide powders of titanium and zirconium.The method of producing these powders using spark machining has been described in detail elsewhere. The carbide is formed during the machining of the metal due to a reaction between the metal and carbon from kerosene which is used as a dielectric for spark machining. The rate of solidification and the carbon content of the carbides can be varied by varying the frequency and polarity of the electric discharge.

Microstructure and Mechanical Properties of Near Eutectic Β-Nial Plus α-Re Alloys Produced by Rapid Solidification and Extrusion

1990 ◽  
Vol 213 ◽  
Author(s):  
D.P. Mason ◽  
D.C. Van Aken
Keyword(s):  
Electron Microscopy ◽  
Rapid Solidification ◽  
Eutectic Composition ◽  
Extrusion Process ◽  
Solid Solution Strengthening ◽  
Size Refinement ◽  
Transmission Electron ◽  
Solution Strengthening ◽  
Rapidly Solidified ◽  
Strengthening Precipitate

ABSTRACTTwo β-NiAl plus α -Re alloys with near eutectic composition were produced by rapid solidification and then consolidated through a powder extrusion process. Microstructures of the rapidly solidified, as-consolidated, and deformed alloys were characterized by transmission electron microscopy. Both compression and tensile properties of these alloys were determined over the temperature range of 300–1300 K. The Re additions were found to greatly enhance low and intermediate temperature yield strengths when compared to other β-NiA1 alloys. This enhancement was attributed to a combination of solid solution strengthening, precipitate hardening, and grain size refinement. Above 1200K the strength of these Re-modified alloys was comparable to the binary β-NiAl compound.

Unusual Rapidity of Electron Beam Transient Tempering

1986 ◽  
Vol 80 ◽  
Author(s):  
Anjum Tauqir ◽  
Peter R. Strutt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Thermal Treatment ◽  
Rapid Solidification ◽  
High Speed ◽  
Defect Cluster ◽  
High Concentration ◽  
Transmission Electron ◽  
Nucleation Sites

AbstractElectron beam rapid solidification of molybdenum-base high speed steels results in quenched-in metastable phases containing a high concentration of alloying elements. Thermal reprocessing of such material by momentary interaction with the electron beam results in decomposition of martensite at a rate ≈ 100 times faster than that occurring during conventional thermal treatment. It is postulated that this arises from a high concentration of 'defect cluster nucleation sites' during the rapid up-quenching. The product of short thermal treatment is a dispersion of 2–5 nm very fine precipitates identified using transmission electron microscopy as MC type carbides.

Transmission electron microscopy investigations of the microstructures in rapidly solidified Mg-Sn ribbons

Micron ◽  
2018 ◽  
Vol 115 ◽  
pp. 1-6 ◽  
Author(s):  
Li Ye ◽  
Yuanlin Zhuang ◽  
Dongshan Zhao ◽  
Shuangfeng Jia ◽  
Jiaping Zhou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Rapidly Solidified

TEM/STEM Characterization of Rapidly Solidified Aluminum Alloys

1985 ◽  
Vol 43 ◽  
pp. 30-31
Author(s):  
R. J. Kar ◽  
T. P. McHale ◽  
R. T. Kessler
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloys ◽  
High Strength ◽  
Advanced Materials ◽  
Structure Property ◽  
Aerospace Applications ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Rapidly Solidified

Low-density and high strength-type rapidly solidified (RST) aluminum alloys offer promise for structural aerospace applications. At Northrop, as part of a continuing program to establish structure-property relationships in advanced materials, detailed transmission electron microscopy (TEM)/scanning transmission electron microscopy (STEM) of candidate RST aluminum-lithium (Al-Li) and high strength (7XXX-type) aluminum-copper-magnesium-zinc (Al-Cu-Mg-Zn) alloys is routinely performed. This paper describes typical microstructural features that we have observed in these alloys.Figure 1 illustrates the microstructure of an inert-gas atomized RST Al-Li-Cu-Mg-Zr alloy. Frequently the grain boundaries are decorated with continuous or semi-continuous stringers of oxide that are relatively opaque to the incident electron beam. These have been identified to be Al-,Mg-, and Li- containing oxides present on powder particle surfaces prior to consolidation, and which have not been adequately broken up and dispersed by post-consolidation processing. The microstructures of these alloys are generally characterized by unrecystallized grains and equiaxed sub-grains pinned by fine (0.2μm) precipitates. These have been identified to be Al3Zr dispersoids using a combination of selected area diffraction/energy-dispersive x-ray (SAD/EDX) methods.

Sign in / Sign up

Export Citation Format

Share Document