Journal
INTERMETALLICS
Volume 137, Issue -, Pages -Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.intermet.2021.107284
Keywords
A; intermetallics; C; single-crystal growth; B; mechanical properties; D; microstructure; Grain boundary
Categories
Funding
- National Key Research and Development Program of China [2017YFB0702902]
- National Natural Science Foundation of China [51471014, 52071007]
Ask authors/readers for more resources
A comparative study was conducted on a novel alloy's microstructure and mechanical properties, showing that the single-crystal alloy exhibited higher yield strength and elongation under tension in various conditions, with excellent ductility, while the polycrystalline alloy lost ductility at high temperatures.
A comparative investigation in microstructure and mechanical properties of a novel as-cast polycrystalline and single-crystal (SC) Co-9Al-9W-2Ta-0.02B-0.02Ce (at.%) alloy with a growth direction of [0 0 1] has been performed. Aged at 900 degrees C for 100 h, the polycrystalline and SC alloy consisted of a Co solid solution (gamma-CoSS) matrix and nano-scale cuboidal gamma '-Co3(Al, W) intermetallic precipitates, while the two phases cohered with each other. For the polycrystalline alloy, Ce was observed to segregate primarily at the grain boundaries and the gamma '-Co3(Al, W) phase, and it could exclude impurity O from the grain boundaries. From room temperature (RT) to 900 degrees C, the SC sample always showed higher yield strength and elongation under tension than the polycrystalline sample except strength at 700 degrees C, while the flow stress anomalies took place at 700 degrees C for the polycrystalline alloy, and 800 degrees C for the SC alloy. Without the grain boundary, the SC alloy had excellent elongation, larger than 15.6% from RT to 900 degrees C. However, the polycrystalline alloy lost the ductility at temperatures above 600 degrees C, which was caused by transformation of the failure from a mixed transgranular dimple plus intergranular brittle mode to fully intergranular brittle mode.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available