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Author Hecht, Ulrike ♦ Witusiewicz, Victor T.
Source SpringerLink
Content type Text
Publisher Springer US
File Format PDF
Copyright Year ©2017
Language English
Subject Domain (in DDC) Technology ♦ Engineering & allied operations
Subject Keyword Engineering ♦ Chemistry/Food Science ♦ Physics ♦ Environment ♦ Earth Sciences
Abstract Controlling the grain size and texture of lamellar TiAl-alloys is essential for well-balanced creep and fatigue properties. Excellent refinement and texture mitigation are achieved in aluminum lean alloys by low boron additions of 0.2 at.%. This amount is sufficient to promote in situ formation of ultrafine borides during the last stages of body centered cubic (BCC) solidification. The borides subsequently serve as nucleation sites for hexagonal close packed (HCP) during the BCC–HCP phase transformation. Bridgman solidification experiments with alloy Ti-43Al-8Nb-0.2C-0.2B were performed under a different growth velocity, i.e., cooling rate, to evaluate the HCP grain size distribution and texture. For slow-to-moderate cooling rates, about 65% of HCP grains are randomly oriented, despite the pronounced texture of the parent BCC phase resulting from directional solidification. For high cooling rates, obtained by quenching, texture mitigation is less pronounced. Only 28% of the HCP grains are randomly oriented, the majority being crystallographic variants of the Burgers orientation relationship.
ISSN 10474838
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2017-08-28
Publisher Institution The Minerals, Metals & Materials Society (TMS)
Publisher Place New York
e-ISSN 15431851
Journal JOM
Volume Number 69
Issue Number 12
Page Count 8
Starting Page 2588
Ending Page 2595

Source: SpringerLink