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Title: The preparation and properties of composite materials based on cubic titanium trialuminide. [64Al28Ti8Fe; 67Al25Ti8Mn]

Journal Article · · Scripta Metallurgica et Materialia; (United States)
;  [1]
  1. Univ. of Neuchatel (Switzerland)

Intermetallics based on Al[sub 3]Ti, particularly when alloyed to the more highly symmetric L1[sub 2] cubic crystal structure, show good strength over the temperature range from room temperature up to about 700C and good oxidation resistance. Unfortunately these materials have poor ambient temperature ductility and toughness. An obvious way to improve this low toughness is to make use of composite philosophy, namely to incorporate second phase ductile particles which could act as crack bridges and delay failure. This article describes some experiments along these lines which show in particular the major problems of reactions occurring during consolidation of powder-source materials, and of internal cracking brought about by differential thermal dilations. The potential of these methods of material preparation for bringing about improvements in toughness of these intermetallics is discussed. Gas atomized powders of two cubic titanium trialuminide alloys were used for the present experiments. These powders were of composition 64% Al, 28% Ti and 8% Fe and 67% Al, 25% Ti and 8% Mn and had mean sizes of about 50[mu]m. Small quantities of powder were mixed with selected elemental powders in the desired proportions and the mixtures were consolidated in steel cans by HIP under a pressure of 100MPa at 1,140 C for 3h followed by slow cooling. The composite materials prepared were: using the Al-Ti-Fe matrix - additions of pure Fe powder in volume proportions of 1.4%, 2.7% and 5.5%; using the Al-Ti-Mn matrix - additions of pure V, Nb or W powders in a constant volume proportion of about 3.6%.

OSTI ID:
6609900
Journal Information:
Scripta Metallurgica et Materialia; (United States), Vol. 28:7; ISSN 0956-716X
Country of Publication:
United States
Language:
English