Experimental synthesis and density functional theory investigation of radiation tolerance of Zr₃(Al_1‐xSi_x)C₂MAX phases

Abstract

Synthesis, characterization and density functional theory calculations have been combined to examine the formation of the Zr 3 (Al 1-x Si x )C 2 quaternary MAX phases and the intrinsic defect processes in Zr 3 AlC 2 and Zr 3 SiC 2 . The MAX phase family is extended by demonstrating that Zr 3 (Al 1-x Si x )C 2 , and particularly compositions with x%0.1, can be formed leading here to a yield of 59 wt%. It has been found that Zr 3 AlC 2 -and by extension Zr 3 (Al 1-x Si x )C 2 -formation rates benefit from the presence of traces of Si in the reactant mix, presumably through the in situ formation of Zr y Si z phase(s) acting as a nucleation substrate for the MAX phase. To investigate the radiation tolerance of Zr 3 (Al 1-x Si x )C 2 , we have also considered the intrinsic defect properties of the end-members. properties (high elastic stiffness, high melting temperature, high thermal shock resistance, good machinability, high thermal, and electrical conductivity). 2,6-12 Such properties drive their technological importance and are attributed to their structure, which consists of the stacking of n "ceramic" layer(s) interleaved by an A "metallic" layer. 2,[6][7][8] MAX phases crystallize with the hexagonal P6 3 /mmc space group (no. 194).1,2 The MAX phase family has three main forms, first M 2 AX (i.e., n=1) type which are commonly --

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

“…The lowest energy Frenkel pair formation energies for Zr, Al and C are 6.66 eV, 1.51 eV and 3.32 eV, respectively (similar to energies reported in [14] ). Unlike the Nb 4 AlC 3 system, the lowest energy Frenkel pair is the A Frenkel ( Supplementary Fig.…”

“…New MAX phase compounds, with an M element of Zr, Nb and/or Ti, have been fabricated as potential fuel cladding coating materials either for ATF applications (LWRs), or for next-generation nuclear systems with corrosive primary coolants (e.g. Gen-IV leadcooled fast reactors, LFRs) [11][12][13][14][15] . Zr-based MAX phases are of particular interest due to the small neutron cross-section of Zr and the promising performance of ZrC-based ceramics in nuclear environments [16 , 17] .…”

Mechanical behavior, bonding nature and defect processes of Mo2ScAlC2: A new ordered MAX phase

“…Additionally, antisite processes could lead to the formation of Mo Al + Al Mo (2.866 eV) and Sc Al + Al Sc (2.835 eV). It can be concluded from these results that other MAX phases such as Ti 3 AlC 2 [60,61] is more radiation tolerant than Mo 2 ScAlC 2 .…”

312 MAX Phases: Elastic Properties and Lithiation

“…Although Mo 3 SiC 2 , Hf 3 AlC 2 , Zr 3 AlC 2, and Zr 3 SiC 2 are of interest, it should be noted that not all of these compounds have been synthesized yet, although there are many reports that provide some of them in stable forms. Specifically, Zhou et al [31] have synthesized an Zr 3 AlC 2 together with Solvas-Zapata et al [32], who synthesized Zr 3 (Al 1−x Si x )C 2 . Regarding Mo 3 SiC 2 , there are many theoretical reports [33] about its properties, like self-healing.…”