You Wang
材料科学技术（英）
The structural, elastic, and electronic properties of NiAl alloyed with rare earth element (REE) Ce have been investigated by using density functional theory (DFT). It is found that Ce has a strong Al site preference and causes lattice distortion of NiAl. The calculation of elastic constants shows that Ce increased both the hardness and the ductility of NiAl, which could be explained by the formation of new ionic bonds between Al (and Ni) and Ce and the enhancement of covalent bonds in Ni8Al7Ce. Our results are in good agreement with the available experimental data and other theoretical results.
关键词:
Point defects
You Wang
材料科学技术（英）
The structural, elastic, and electronic properties of NiAl alloyed with rare earth element (REE) Ce have been investigated by using density functional theory (DFT). It is found that Ce has a strong Al site preference and causes lattice distortion of NiAl. The calculation of elastic constants shows that Ce increased both the hardness and the ductility of NiAl, which could be explained by the formation of new ionic bonds between Al (and Ni) and Ce and the enhancement of covalent bonds in Ni8Al7Ce. Our results are in good agreement with the available experimental data and other theoretical results.
关键词:
Point defects
You Wang
材料科学技术（英）
In this paper, the microstructure of WC-Co alloys with and without nano-additives was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hardness and fracture toughness was tested by using a Vickers hardness tester and a universal testing machine. The cutting test was carried out at di®erent feed velocities (250 r/min and 320 r/min), and the contact pairs are cutting tools and 45# steel bars. Results showed that the hardness and fracture toughness of WC-Co cemented carbides with nano-additives are higher than that of WC-Co cemented carbides without nano-additives, and they are increased 10.21% and 19.69%, respectively. The flank worn width and crater width of cutting tools decrease
greatly with the addition of nano-additives. For the nano-modified specimen with WC grain size of 7μm, both the flank worn width and crater width are the minimum after the cutting process. And there are little built-up layers and some pile-up regions on the flank face leading to high cutting performance for the nano-modified cemented carbides. There are some melted regions on the flank face of cutting tools without nano-additives, and the WC grains on the cross section of alloys without nano-additives show severe fragmentation. The wear type of WC-Co is flank wear, and the wear mechanism is abrasive, adhesion and oxidation wear.
关键词:
Cutting tools
