Design of highly thermal-shock resistant tungsten alloys with nanoscaled intra- and inter-type K bubbles

Abstract Tungsten alloys with high strength, high toughness and high-temperature stability are strongly desired in extreme conditions. The nanoengineering of potassium bubbles (5–50 nm) is a fascinating strategy to strengthen these properties. However, such nano potassium bubbles can only be acquired in tungsten wires through swaging and drawing process till now. Here, we report an intra- and inter-potassium nano-bubbles strengthened bulk tungsten fabricated via an industrially applicable process combining aluminum-potassium-silicon (AKS) doping and spark plasma sintering (SPS), which exhibits desirable strength and remarkable toughness, as well as high thermal-shock resistance. The AKS-doping incorporated the K-Al-Si-O particles inside the W grains and the rapid high-temperature sintering of SPS produced the nanometer K bubbles from the K-Al-Si-O particles and kept the K bubbles inside the W grains. Our K-bubble strengthened tungsten material displays high potential in high-temperature applications. This strategy is also potentially applicable to other refractory metals such as molybdenum.