High-temperature tensile and thermal shock characterization of low-temperature rolled tungsten

A developed tungsten (W) grade was prepared by powder metallurgy technology plus multi-step low-temperature rolling. The relative density, thermal conductivity, microstructure, tensile properties of original and hightemperature annealed states, micro-hardness and transient thermal shock resistance were characterized. The results of tensile test with a strain rate of 2 x 10(-4) s(-1) show that the ductile-brittle transition temperature (DBTT) of rolled-W in the original and recrystallized state are 150-200 degrees C and 250-300 degrees C, respectively. The rolled-W presents high strength and great plasticity simultaneously. For example, the maximum ultimate tensile strength (UTS) below DBTT is as high as similar to 1189 MPa, and the maximum total elongation (TE) above DBTT reaches 28.9 %. In particular, the TE of recrystallized W achieves an incredible 81.4 % at 500 degrees C, which is the highest value among all the published literatures so far. The results of transient thermal shock tests indicate that the rolled-W has an outstanding transient thermal shock resistance. It can withstand the thermal bombardment at an absorbed power densities (APD) of 0.33 GW center dot m(-2) without causing any surface damages, and still no cracks are observed as the APD rises to 0.88 GW center dot m(-2). Moreover, the failure mechanism of rolled-W was also studied in details. This work plays an important role in establishing a dependable China Fusion Engineering Test Reactor (CFETR) data-library on a unitary W grade, which can provide an effective reference for the identification of material performance under the high heat flux and subsequent numerical simulation.

Automated summary

A developed tungsten grade with high strength and great plasticity was prepared through powder metallurgy technology and low-temperature rolling. The material exhibited excellent tensile properties, with a high ductile-brittle transition temperature and high ultimate tensile strength. It also showed outstanding transient thermal shock resistance, with the ability to withstand high absorbed power densities without surface damages or cracks. This work is important for establishing a reliable data-library for a unitary tungsten grade in China Fusion Engineering Test Reactor (CFETR) and can provide valuable insights for material performance identification and subsequent numerical simulations.