Study on diffusion characteristics of Al-Cu systems and mechanical properties of intermetallics

The kinetics of reaction diffusion in Al-Cu binary systems at solid-state temperatures was experimentally investigated. The Al-Cu diffusion couples were heat treated in the temperature rang of 673-813 K for different period of time, respectively. A layer of intermetallic compounds (IMCs) consisting of 0(Al2Cu), f12(Al0.939Cu0.987), C2(Al9Cu11.5) and gamma 1(Al4Cu9) phases was formed in the diffusion region. The thickening of all four IMCs follows a parabolic growth pattern, which can be used to estimate the growth constants of the IMCs. The composition of IMC was quantitatively analyzed by electron probe microanalysis (EPMA), and the interdiffusion coefficients and activation energies were evaluated for each phase. The nanoindentation technique was employed to obtain the hardness, Young's modulus and creep stress index of the IMCs. It was demonstrated that the C2(Al9Cu11.5) phase has the greatest hardness of 11.94 GPa, while gamma 1(Al4Cu9) has the largest Young's modulus of 254.69 GPa and the minimum creep stress index of 10.75. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Experimental investigation of reaction diffusion kinetics in Al-Cu binary systems at solid-state temperatures revealed the formation of intermetallic compounds with different compositions, showing parabolic growth in thickness. Quantitative analysis of the composition and characterization of properties using electron probe microanalysis and nanoindentation techniques were conducted to evaluate diffusion coefficients, activation energies, hardness, Young's modulus, and creep stress index of the IMCs.