Effect of Precipitation on the Hardness of Ternary Metallic Glass

Abstract

The present study reports effects of annealing treatment on the hardness of Ce 75 Al 23 Si 2 rare earth-based metallic glasses (REMG). Then specimens were annealed at 100˚C, 200˚C, 250˚C, 270˚C, and 290˚C five different temperatures for 30 minutes. After that, three different characteristic methods, including microindentation, X-ray Diffraction (XRD), and scanning electrical microscope (SEM) were conducted on the as received REMG sample and five annealed samples. XRD data demonstrate that the crystallization occurs in the sample at the annealing temperature as low as 200˚C. The microindentation measurement shows that hardness of the REMG sample does not change at all before crystallization occurs in the sample and increases with the annealing temperature in the range of 200˚C to 290˚C. The average crystal size in the annealed samples was estimated using Debye-Scherrer equation to be 28-42 nm, in consistent with the SEM observation, indicating that nano-crystalline domains may give rise to the enhancement of hardness.

Effects of Bi Addition on the Microstructure and Mechanical Properties of Nanocrystalline Ag Coatings

“…This difference indicates that the addition of Bi would also lead to a smaller grain size. The smaller crystalline size would lead to the higher yield strength according to the Hall-Petch relationship [ 55 , 56 , 57 ]. Meanwhile, it is worth pointing out that there is no intermetallic compound in the current electrodeposited process and we did not observe bright spots from the high-angle annular dark-field (HAAFD) TEM tomography as previously prepared Ni-Bi coatings [ 14 ].…”