Dilatometry of Refractory Metals and Alloys Using Multi- Wavelength Laser Shadowgraphy of Filament Samples

Document Type : Original Article


1 Department of Physics, Faculty of Science, Cairo University, Egypt.

2 Laser Photonics Research Center, Engineering Physics Department, Military Technical College, Cairo, Egypt.


In this work, we discuss a new technique for measuring the linear thermal expansion of refractory metals and alloys over their entire temperature range from room to near melting. The technique is based on generating multi-wavelength laser shadowgraphs for filament wire samples under gradual heating, and measuring the dimensional changes from its shadowgraphs using digital camera. The samples are clamped from both ends and joule heated by direct current under vacuum. The measurements are non-contact and accurate, enabling low cost dilatometric measurements that help in future synthesis and test of new grade of refractory materials, used as plasma facing material in nuclear fusion reactor, or special super alloys for high temperature applications were thermal structural stability are required.