Room-temperature deformation mechanisms and the defect structure of tungsten carbide

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.

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A comparative study of plastic deformation mechanisms in room-temperature and cryogenically deformed magnesium alloy AZ31

Materials Science and Engineering A ◽

10.1016/j.msea.2021.140821 ◽

2021 ◽

Vol 807 ◽

pp. 140821

Author(s):

Kai Zhang ◽

Zhutao Shao ◽

Christopher S. Daniel ◽

Mark Turski ◽

Catalin Pruncu ◽

...

Keyword(s):

Plastic Deformation ◽

Magnesium Alloy ◽

Comparative Study ◽

Room Temperature ◽

Deformation Mechanisms ◽

Alloy Az31 ◽

Magnesium Alloy Az31

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Room-temperature deformation of single crystals of ZrB2 and TiB2 with the hexagonal AlB2 structure investigated by micropillar compression

Scientific Reports ◽

10.1038/s41598-021-93693-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zhenghao Chen ◽

Bhaskar Paul ◽

Sanjib Majumdar ◽

Norihiko L. Okamoto ◽

Kyosuke Kishida ◽

...

Keyword(s):

Single Crystals ◽

Plastic Flow ◽

Room Temperature ◽

Resolve Shear Stress ◽

Temperature Deformation ◽

Slip Systems ◽

Compression Tests ◽

Plastic Deformation Behavior ◽

Bulk Single Crystals ◽

Micropillar Compression

AbstractThe plastic deformation behavior of single crystals of two transition-metal diborides, ZrB2 and TiB2 with the AlB2 structure has been investigated at room temperature as a function of crystal orientation and specimen size by micropillar compression tests. Although plastic flow is not observed at all for their bulk single crystals at room temperature, plastic flow is successfully observed at room temperature by the operation of slip on {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 3> in ZrB2 and by the operation of slip on {1$${\bar{1}}$$ 1 ¯ 00}<0001> and {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 0> in TiB2. Critical resolve shear stress values at room temperature are very high, exceeding 1 GPa for all observed slip systems; 3.01 GPa for {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 3> slip in ZrB2 and 1.72 GPa and 5.17 GPa, respectively for {1$${\bar{1}}$$ 1 ¯ 00}<0001> and {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 0> slip in TiB2. The identified operative slip systems and their CRSS values are discussed in comparison with those identified in the corresponding bulk single crystals at high temperatures and those inferred from micro-hardness anisotropy in the early studies.

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