Transmission Electron Microscopy of Rapidly Solidified Du-5% W Alloy

1991 ◽  
Author(s):  
Ravi Batra
Micron ◽  
2018 ◽  
Vol 115 ◽  
pp. 1-6 ◽  
Author(s):  
Li Ye ◽  
Yuanlin Zhuang ◽  
Dongshan Zhao ◽  
Shuangfeng Jia ◽  
Jiaping Zhou ◽  
...  

Author(s):  
R. J. Kar ◽  
T. P. McHale ◽  
R. T. Kessler

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.


2011 ◽  
Vol 465 ◽  
pp. 199-202 ◽  
Author(s):  
Alena Michalcová ◽  
Dalibor Vojtěch ◽  
Pavel Novák ◽  
Ivan Procházka ◽  
Jakub Čížek ◽  
...  

An alloy containing Al – 3wt.% Cr – 3wt.% Fe – 0.8wt. % Ce, was prepared by melt spinning. Structure of obtained ribbons was observed by light, scanning and transmission electron microscopy. It was found out that the structure is very fine. Microhardness of cross sectioned ribbons was also measured. Defects in structure were determined by positron annihilation spectroscopy. The thermal stability of the alloy was observed by comparing rapidly solidified ribbons and ribbons annealed at 400°C and at 500°C for 100 h


Author(s):  
C. S. Pande ◽  
S. Smith

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.


1983 ◽  
Vol 28 ◽  
Author(s):  
S. K. Das ◽  
E. M. Norin ◽  
R. L. Bye

ABSTRACTA series of rapidly solidified Ni-Mo-Cr-B alloys have been investigated for possible application as corrosion resistant hardfacing coatings. As-cast amorphous ribbons were pulverized to powder, which was subsequently applied to a substrate by plasma spraying. The coatings are substantially amorphous, as revealed by x-ray diffraction and transmission electron microscopy. They exhibit ∼95% of theoretical density and exhibit good corrosion and wear resistances, superior to those of many commercially available hardfacing coatings.


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