|About this Abstract
||Materials Science & Technology 2011
||Advanced Protective Coatings for Refractory Metals and Alloys
||Balancing the Properties of Structural Mo-Borosilicide Alloys for Ultra-High Temperature Applications
||Martin Heilmaier, Manja Krueger, Heinrich Kestler, Steffen Burk, H.J. Christ
|On-Site Speaker (Planned)
We review our current state of research on Mo-Si-B alloys for structural applications in excess of 1100°C in air. This presentation will demonstrate that the presence of a continuous Mo-matrix with finely dispersed intermetallic phases Mo<sub>3</sub>Si and Mo<sub>5</sub>SiB<sub>2</sub>, manufactured via a powder-metallurgical process, seems to best fulfil these requirements: first, a reduction of brittle-to-ductile transition temperature by more than 150 K was obtained (together with micro-alloying of Zr to enhance grain boundary strength). Second, the creep behaviour was determined to be superior to the state-of-the art single crystal Ni-base superalloy CMSX-4 at temperatures above 1300 K. Third, oxidation trials in synthetic air show after an initial weight loss due to MoO<sub>3</sub> sublimation the formation of a dense borosilicate glass layer above 1300 K which protects the base alloy. Finally, burner rig tests in combustion environment of the base alloy and a SIBOR coated alloy show results comparable to CMSX-4.
||Definite: A CD-only volume