The Stability of Irradiation-Induced Defects in Zr ₃AlC ₂, Nb ₄AlC ₃ and (Zr _0.5,Ti _0.5) ₃AlC ₂ Max Phase-Based Ceramics

Abstract

Publisher's PDF, also known as Version of record Cyswllt i'r cyhoeddiad / Link to publication Dyfyniad o'r fersiwn a gyhoeddwyd / Citation for published version (APA): a b s t r a c tThis work is a first assessment of the radiation tolerance of the nanolayered ternary carbides (MAX phases), Zr 3 AlC 2 , Nb 4 AlC 3 and (Zr 0.5 ,Ti 0.5 ) 3 AlC 2 , using proton irradiation followed by post-irradiation examination based primarily on x-ray diffraction analysis. These specific MAX phase compounds are being evaluated as candidate coating materials for fuel cladding applications in advanced nuclear reactor systems. The aim of using a MAX phase coating is to protect the substrate fuel cladding material from corrosion damage during its exposure to the primary coolant. Proton irradiation was used in this study as a surrogate for neutron irradiation in order to introduce radiation damage into these ceramics at reactorrelevant temperatures. The post-irradiation examination of these materials revealed that the Zr-based 312-MAX phases, Zr 3 AlC 2 and (Zr 0.5 ,Ti 0.5 ) 3 AlC 2 have a superior ability for defect-recovery above 400 °C, whilst the Nb 4 AlC 3 does not demonstrate any appreciable defect recovery below 600 °C. Density functional theory calculations have demonstrated that the structural differences between the 312 and 413-MAX phase structures govern the variation of the irradiation tolerance of these materials.

Processing of MAX phases: From synthesis to applications

“…103,104 Furthermore, Zr-and Nb-based MAX phases have been recently considered due to the small neutron cross-section of Zr and the favorable refractory metal properties of Nb. 105 The post-irradiation examination revealed that Zr 3 conditions due to the preference for M:A antisites and C Frenkel pairs at the M-2 layer. 105…”

Molten salt synthesis and formation mechanisms of ternary V‐based MAX phases by V–Al alloy strategy

“…The MAX phase is named after its distinct layered structure and chemical composition, where M is an early transition metal, A represents an A-group element, and X can be carbon and nitrogen. The solid covalent bonding between M and X endows MAX phase with high elastic modulus, [6][7][8][9][10] outstanding damage tolerance, 11,12 certain mechanical properties, [13][14][15] and the high partial density of states (PDOS) value of the M elements at the Fermi level gives the MAX phase extra electrical conductivity. 16,17 The relatively weak interaction between MX and A makes A layers easily be etched by oxidizing acids or salts, leading to the emergence of a new series of two-dimensional materials named MXene.…”