THE INFLUENCE OF TEXTURE ON THE CREEP BEHAVIOUR OF THE ODS NICKEL-BASE ALLOY PM 1000 M. Heilmaier 1 *, F.E.H. Mu ¨ller 2 , G. Eisenmeier 3 and B. Reppich 3 1 Department of Mechanical and Materials Engineering, University of Western Australia, Nedlands, W.A. 6907, Australia 2 Plansee AG, PM ODS Materials, A-6600 Reutte, Tyrolia, Austria 3 Institut fu ¨r Werkstoffwissenschaften, Lehrstuhl I, Universita ¨t Erlangen-Nu ¨rnberg, D-91058 Erlangen, Germany (Received July 7, 1998) (Accepted July 28, 1998) Introduction Oxide dispersion strengthened (ODS) nickel-base alloys are considered to be potential candidate materials for high temperature applications in excess of 1000°C. Their extraordinary creep resistance results from a beneficial superposition of strengthening by incoherent, finely dispersed oxide particles, which effectively interact with dislocations (1,2), and of coarse, elongated grains suppressing grain boundary sliding (3). While these mechanisms have been convincingly discussed in the literature (3,4), the influence of texture on creep strength has not been treated equally systematically due to the lack of varying the grain orientation or texture independently on the grain structure during the final recrystal- lization heat treatment. The availability of appropriate material of the ODS nickel-base alloy PM 1000 (trademark of Plansee AG, Reutte, Austria) enables to investigate creep specimens taken from the same heat with different grain orientations but identical grain and particle structure. Thus, in the present work we will show that texture significantly affects not only the point of maximum deformation resistance (or steady-state flow stress, respectively) but also the homogeneity of deformation. Experimental Details The austenitic nickel-base alloy PM 1000 having the nominal chemical composition (wt.%) of Ni-20Cr-0.5A1-0.3Ti-0.6Y 2 O 3 was supplied in the fully recrystallized condition (final annealing treatment: 1h at 1315°C) in form of the following two heats: a) a sheet material (thickness 13 mm) manufactured by (hot) cross-rolling and b) a hot extruded bar material (diameter 50 mm) with the grain parameters inspected by optical microscopy (OM) and listed in Table 1. The orientation of coarse individual grains was measured by scanning electron microscopy (SEM, Zeiss DSM 962) using electron back scattering pattern (Nordif-EBSP-system). Transmission electron microscopy (TEM, Jeol CM 200 X) has been used for determining the parameters of the Yttrium-Aluminium oxide dispersoids: for both heats one obtains a mean particle diameter of d = 14 nm, a planar centre to centre spacing of L = 100 *Permanent address: Institut fu ¨r Festko ¨rper- und Werkstofforschung Dresden, Helmholtzstrasse 20, D-01069 Dresden, Germany. Pergamon Scripta Materialia, Vol. 39, No. 10, pp. 1365–1370, 1998 Elsevier Science Ltd Copyright © 1998 Acta Metallurgica Inc. Printed in the USA. All rights reserved. 1359-6462/98 $19.00 + .00 PII S1359-6462(98)00322-4 1365