Effect of Microstructure Changes on Mechanical Properties of La₆₆Al₁₄(Cu, Ni)₂₀ Amorphous and Crystalline Alloys
Author(s)Zhang, Yong; Lee, Irene Mei Ling; Tan, Hao; Jing, Qin; Li, Yi
The microstructure, and phase selections of La₆₆Al₁₄(Cu, Ni)₂₀ alloy were studied by Bridgman solidifications, and composite materials of dendrites in amorphous matrix or micro- and nano- sized eutectic matrix were formed with different cooling rates. The volume fraction of the dendrite phase reaches a maximum at the cooling rate of about 15 K/s, the secondary dendrite arm spacing λ₂ decreases from 4.3 µm to 0.6 µm with the increasing of cooling rate R, and obeys the equation of λ₂R⁰.⁵⁷=1.74µm(K/s)R⁰.⁵⁷. The compression strength, as well as the elastic strain limit of the dendrite/amorphous matrix composite are 600 MPa, and 2.3%, respectively. Improved ductility was observed for the dendrite amorphous matrix composites with more dendrite phase by slow cooling rate.
Advanced Materials for Micro- and Nano-Systems (AMMNS);
Bridgman solidification, bulk metallic glass, eutectic, La-based alloy