Precipitation hardened Copper-Chromium-Zirconium (CuCrZr) alloy is a prime
candidate for divertor components in future European DEMOnstration fusion reactors. To develop the DEMO Design Criteria for In-vessel Components (DDC-IC), the failure criterion of CuCrZr needs to be investigated. Hence, the effects of stress triaxiality and loading strain rate on the fracture ductility of solution heat treated and annealed CuCrZr alloys was studied using digital-imaging-correlation and electron microscopy techniques. It was found that an increase in the stress triaxiality caused a significant decrease of over 50% in the equivalent strain to fracture.