X-ray stress measurement for TiAl intermetallic compound of interest as a new structural material was investigated. Arc-melted Ti-48mol% Al alloy employed in this study exhibited rather preferred orientation because of its lamellar structure. Two approaches were adopted to the measurement for TiAl(311) plane by using Cr-Kα characteristic radiation and a position sensitive proportional counter (PSPC): an oscillation method and a method utilizing only two {311} reflections that belong to one zone axis.
The results obtained are summarized as follows:
(1) The measurement with the oscillation method resulted in the X-ray stress constant, K=-383MPa/deg, and X-ray elastic constant, Ex/(1+νx)=129GPa or Ex=166GPa.
(2) The X-ray value of Ex in TiAl phase was intermediate between the mechanical values of Young's modulus of the present material and Ti-50mol% Al consisting of almost TiAl single phase reported by R.E. Schafrik.
(3) The X-ray stress constant determined by the latter method was -347MPa/deg and agreed nearly with that obtained by the former method.
(4) The non-linearity observed in sin2ψ diagram was caused by X-ray optics of the fixed ψ0 method. The oscillation method by using PSPC was, however, considered to be able to provide the reliable approximate values of K and Ex by reason of above (1) and (2).