Alloy Allvac 718Plus has been marketed by Allvac claiming better mechanical properties at temperatures where In718 has already exhausted its applicability, above the 650ºC range. Allvac 718Plus also assures that it holds improved metallurgical stability at even higher temperatures, up to 700ºC. In this upper range, no degradation of mechanical properties is said to happen in the new alloy. A European R&D project named VITAL dedicated part of its efforts to assess these claims and verify the improvements. Castability and forgeability assessments where completed, together with trials on weldability of the alloy. Mechanical tests and microstructural assessments on both alloys, 718 and 718Plus, in both materials forms, cast and wrought, and two different material conditions, as-heat treated and exposed to service temperatures, were completed and direct comparisons then established. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.
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