Atom probe study of the segregation behaviour of molybdenum-rhenium alloys

✍ Scribed by MC Dolezal; W Athenstaedt; M Leisch

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 184 KB
• Volume: 50
• Category: Article
• ISSN: 0042-207X
• DOI: 10.1016/s0042-207x(98)00061-x

✦ Synopsis

The segregation behaviour on (110)-oriented Mo 0.75 Re 0.25 single crystal tips has been studied by 3D atom probe. In depth profiling measurements after annealing, Re enrichment on the surface was observed. The Re enrichment is found to be limited to the first three atomic layers. An oscillatory behaviour is not observed. The observed segregation behaviour on the (110) plane can be explained in one respect by the particular geometry of the field emitter specimen and the resulting surface relaxations on the apex of the tip and, on the other hand, by the different heats of vaporisation of the two elements Mo and Re. The measured alternating arrival of field evaporated Mo and Re surface atoms gives reason for short range ordering on the reconstructed surface.