Functionally Graded Composite Plate for Plasma Facing Components

Plasma facing components must withstand plasma-wall interactions with minimal plasma contamination or wall erosion. Additionally, they must possess high thermal conductivity, should reflect neutrons, have low tritium absorption, resist creep, and have sufficient ductility/toughness to withstand a wide range of load conditions. No one material contains an ideal mix of these properties. However, tungsten based material is expected to possess superior performance in the divertor where lower-temperature plasma interaction is intended. Unfortunately, currently available tungsten plate is not sufficient for long-life operation in ITER. In order to balance properties and generate materials with high performance, we will create a micro- composite of tungsten alloy and copper. This composite will be graded in composition from the inner surface of the first wall (pure W) to the coolant surface (where excellent thermal and mechanical contact with the backing/heat sink material is required). This composite will be formed using two approaches and then subjected to severe plastic deformation. Utilizing our bulk shear processing technology along with conventional metal-metal composite fabrication methods, we will create a creep resistant, ductile, radiation resistant composite with aligned architecture that optimizes the through-thickness thermal conductivity. Shear Form, Inc. plans to produce ~2x2x10cm composite bars for testing and evaluation. Microscopy, thermal conductivity, and tensile testing will be conducted on a range of morphologies and compositions. The primary commercial application of this engineered material is ITER divertor first wall panels. There exist other opportunities for the technology developed in this work: Rail gun rails, high energy plasma physics, and any other application where extreme heat must be conducted away.