Abstract
Nanometric particles of a new chromium structure were produced by mechanical alloying of Cr3P2 under low nitrogen pressure. X-ray diffraction study has shown that the particles have an ordinary bcc structure of chromium (α-Cr) up to 1 h of milling but they have a new cubic chromium A15-type structure (δ-Cr), up to 2 h of milling, with a lattice parameter equal to 0.4703 ± 0.001 nm. The new structure has a Pm-3 space group with eight atoms distributed within the unit cell: 2 Cr atoms with occupancy equal to 1 in positions: 1a: 000 and 1 b: ½½½ in addition to 6 others Cr atoms with occupancy equal to 0.25 in positions: 6f: ¼ 0 ½; 6f: ½ ¼ 0; 6f: 0 ½ ¼; 6f: ¾ 0 ½; 6f: ½ ¾ 0; 6f: 0 ½ ¾. As well as the new δ-Cr A15-type phase two chromium phosphides are formed in the nanometric Cr3P2 alloy: an orthorhombic CrP and the monoclinic CrP2 after 1 and 2 h of milling, respectively. Therefore, the formed phosphide records the highest density of dislocations and the lowest stacking fault probability after 2 h of milling. The mechanical properties show that the P and CrP are auxetic strong reentrant cellular structures with negative Poisson’s ratio which makes them specifically resistant.
Graphical Abstract
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Disclosure statement
No potential conflict of interest was reported by the authors.