Liquidesolid reaction mechanism in Al-ZrO2(-B2O3) system and the preparation of (α-Al2O3+ZrB2/ZrAl3)/Al composites

Designing of Al based composites with enhanced high temperature strength is of great significance nowadays. In this paper, an (alpha-Al2O3+ZrB2)/Al composite has been prepared utilizing the liquid-solid reaction of Al-ZrO2-B2O3 system, while an (alpha-Al2O3+ZrAl3)/Al composite was synthesized through Al-ZrO2 for comparison. Nano-sized Al2O3 and micron ZrAl3 particles have been in-situ formed in the (5.5Al(2)O(3)+14ZrAl(3))/Al composite, in which the coarse ZrAl3 particles are regarded harmful for the composite's properties. By promoting the reaction between ZrAl3 and B2O3, nano-sized Al2O3 and ZrB2 particles have been synthesized in the (13.8Al(2)O(3)+9.2ZrB(2))/Al composite. Based on the results of X-ray diffraction and electron backscatter diffraction, the Al matrix of the two extruded composites both prefer to form fiber texture (< 111 >(Al)//ED) in the longitudinal section, while the small difference between them is regarded relating to the distributing orientation of D0(23)-ZrAl3 particles. Compared with (Al2O3+ZrAl3)/Al composite, the (Al2O3+ZrB2)/Al composite exhibits more excellent properties. The ultimate tensile strength can reach 463 MPa at 25 degrees C and 188 MPa at 350 degrees C. (C) 2020 Elsevier B.V. All rights reserved.