ISSN:
1662-8985
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Ni3Al shows the unique feature of increasing strength with increasing temperature.However, it is too brittle to use as a structural material due to grain boundary weakness. Ductilitycould be enhanced by controlling grains using directional solidification. In order to increase theductility or strength of Ni3Al alloys, a ductile γ (Ni-rich) phase of dendrite fibers or a strong β(NiAl) phase of dendrite fibers were arrayed in the γ´ (Ni3Al) matrix by directional solidification.The dendrite spacing could be controlled by varying the solidification rates, and the volume fractionof the γ or β phase could be changed by using alloy compositions, from 23 to 27 at. % Al-Ni alloy.With increasing solidification rates, the dendrite spacing decreased, which caused the tensilestrength to be enhanced and the elongation to decrease, evidently due to the phase boundaryaugmentation. With increasing Al content, the γ dendritic microstructure changed to β dendrites inthe γ´ matrix, which resulted in a decrease in elongation as a result of an increase in the volumefraction of the brittle β dendrites in the γ´ matrix
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.29-30.71.pdf
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