Abstract
In this paper the creep behaviour of two model cast Ni-Cr-W-C alloys with different contents of Cr, W and Fe was investigated. Uniaxial tensile creep tests were carried out at temperatures from 1023 to 1273 K and at the applied stress ranged from 20 to 250 MPa. A comparison between the creep characteristics of the two model alloys under comparable creep conditions shows that solid solution strengthening is strongly dependent on the tungsten content for temperatures up to 1173 K. By contrast, no substantial effect of a different content of W on the creep rate and the creep life was found for temperatures above 1273 K when an intensive precipitation of secondary tungsten carbides occurred.

Key words
cast nickel superalloys, high temperature creep, creep rate, creep lifetime, solid solution strengthening, precipitation strengthening

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