Authors: Thomas Voisin JeanPhilippe Monchoux Marc Thomas Christophe Deshayes Alain Couret
Publish Date: 2016/10/20
Volume: 47, Issue: 12, Pages: 6097-6108
Abstract
This paper presents a study of the mechanical properties at room and high temperature of the boron and tungsten containing IRIS alloy Ti48Al2W008B at pct This alloy was densified by Spark Plasma Sintering SPS The resultant microstructure consists of small lamellar colonies surrounded by γ regions containing B2 precipitates Tensile tests are performed from room temperature to 1273 K 1000 °C Creep properties are determined at 973 K 700 °C/300 MPa 1023 K 750 °C/120 MPa and 1023 K 750 °C/200 MPa The tensile strength and the creep resistance at high temperature are found to be very high compared to the data reported in the current literature while a plastic elongation of 16 pct is preserved at room temperature A grain size dependence of both ductility and strength is highlighted at room temperature The deformation mechanisms are studied by postmortem analyses on deformed samples and by in situ straining experiments both performed in a transmission electron microscope In particular a low mobility of nonscrew segments of dislocations at room temperature and the activation of a mixedclimb mechanism during creep have been identified The mechanical properties of this IRIS alloy processed by SPS are compared to those of other TiAl alloys developed for hightemperature structural applications as well as to those of similar tungsten containing alloys obtained by more conventional processing techniques Finally the relationships between mechanical properties and microstructural features together with the elementary deformation mechanisms are discussedThis study has been conducted in the framework of the cooperative project “IRISANR09MAPR001806” supported by the French Agence Nationale de la Recherche ANR which is acknowledged The CEMES group thanks the PNF2 for providing SPS facilities Plateforme Nationale de Frittage Flash/CNRS in Toulouse France
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