Strength adjust mechanism of high toughness Al4C3/Al-xMg composites

Abstract In this paper, Al4C3 was in-situ synthesized in Al4C3/Al-xMg (x = 0, 8 wt%) composites by liquid-solid reaction, the corresponding microstructure evolution and strength adjust mechanism were systematically studied. The Al4C3 particles in-situ generated in Al4C3/Al-xMg composites are both submicron and nanoscale. By adding 8 wt% Mg to Al4C3/Al composite, high content of Mg atoms dissolve in the matrix, which affects the distribution of Al4C3 and plays an active role in improving the mechanical properties. The ultimate tensile strength of the Al4C3/Al–8Mg composites at room temperature increases from 171 MPa to 435 MPa, and the elongation still holds about 17.8%. The Brinell hardness was 105.8 HBW, 2.04 times higher than Al4C3/Al composite. What's more, the introduction of 8 wt% Mg weakens the fiber texture strength of Al4C3/Al composite, changes the preferred orientation from Al//ED to Al//ED, and increases the recrystallization fraction from 36.5% to 56.4%. Therefore, the work hardening ability of the Al4C3/Al–8Mg composites in the deformation process is significantly improved. This work provides a new perspective for designing high strength and toughness aluminum alloy strengthened by solid solution and in-situ nanoparticles simultaneously through liquid-solid method.