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An investigation of the fatigue and fracture behavior of Mn-containing gamma titanium aluminides

Journal Article · · Metallurgical Transactions, A
DOI:https://doi.org/10.1007/BF02671243· OSTI ID:116042
; ;  [1];  [2]
  1. Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering
  2. General Electric Research and Development, Schenectady, NY (United States)

The fatigue and fracture mechanisms in Ti-48Al-xMn (x = 1.4 to 2.0 at. pct) gamma-based titanium aluminide alloys are elucidated. Unlike most gamma alloys, which fail predominantly by transgranular fracture at room temperature, fracture in ternary Ti-48Al-xMn alloys is shown to occur mainly by intergranular failure. The incidence of intergranular failure increased with increasing annealing duration and temperature. Intergranular fracture is shown to occur as a result of the segregation of Mn to equiaxed and interlamellar boundaries. Annealing either above or below the eutectoid temperature results in the precipitation of {alpha}{sub 2} particles. The reduction in the strength and toughness of ternary Mn-containing alloys is attributed to the combined effects of segregation and {alpha}{sub 2} precipitation. A micromechanics framework is presented for the assessment of twin toughening mechanisms under monotonic and cyclic loading.

Sponsoring Organization:
USDOE
OSTI ID:
116042
Journal Information:
Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 9 Vol. 26; ISSN 0360-2133; ISSN MTTABN
Country of Publication:
United States
Language:
English