"Cr3Si has many desirable properties for use as a high temperature structural material: a high melting point, high stiffness and good chemical resistance. However, like many intermetallics, it suffers from a low toughness at room temperature. To overcome this limitation, ductile second phase toughening has been examined using chromium as the second phase.
Specimens of Cr-Cr3Si composites were produced by powder metallurgy techniques. The mechanical properties of these composites were evaluated using microhardness indentation to calculate a toughness value and in some cases notched three- point bend bars were also used. Examination of the Cr phase of these composites indicated that it lacked sufficient toughness itself to produce the desired toughness in the composite. Mechanical alloying was then used to create chromium alloys that were hot pressed and tested using the three-point bend method. The addition of 0.5 at. % V to Cr with 7.0 at.% Si (representative of the chromium phase of the composite) showed the largest increase in toughness, a 60% increase. Chromium with 0.5 at. % V was then used to make a composite with Cr3Si.
Mechanical alloying was also used to produce a (Cr,Mo)3Si material, which should have superior high temperature properties compared to Cr3Si. This material was then used to produce composites with Cr and Cr-0.5 V. The composites had twice the toughness compared with similar composites produced with Cr3Si"--Abstract, page iv.
Newkirk, Joseph William
Askeland, Donald R.
Van Aken, David C.
Kohser, Ronald A.
Ownby, P. D.
Materials Science and Engineering
Ph. D. in Metallurgical Engineering
University of Missouri--Rolla
xi, 136 pages
© 1998 Terry Alan Cruse, All rights reserved.
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Cruse, Terry Alan, "Examination of chromium-chromium silicide composites and methods of improving toughness" (1998). Doctoral Dissertations. 1262.
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