Tungsten foil laminate for structural divertor applications – Basics and outlook

Abstract

It has been attempted for several years to synthesize a tungsten material with a low brittle-to-ductile transition temperature and a high fracture toughness that can be used for structural parts. In this work, we show how to realize the ductilization of tungsten: by synthesizing a laminate made of tungsten foil.This paper shows that tungsten foil is ductile in a tensile test performed at room temperature. The idea now is to expand the ductile material properties of the tungsten foil to a bulk, by assembling several layers of this ductile tungsten foil. By doing this, a tungsten laminate can be synthesized. This laminate is characterized by a Charpy impact test and the results are compared to tungsten plate material. The results of the tungsten laminate are excellent: nearly 2J of energy absorption at room temperature, 5J at 100°C and 10J at 300°C (measured by KLST standard). Even more overwhelming are the results obtained from a tungsten laminate synthesized with recrystallized tungsten foil (annealed for 1h/1800°C). Here, the brittle ductile transition is at 500°C, which is an improvement of at least 500°C compared to recrystallized plate material (1h/2000°C).As a last step we present the first ductile tungsten pipe that can be used for structural applications: a tungsten pipe made of tungsten foil.