Evidence of dislocation cross-slip in MAX phase deformed at high temperature

The paper reviews the results of using the process of self-propagating high-temperature synthesis (SHS) to obtain high-temperature nickel alloys and composites based on titanium carbide (TiC) and nickel. In order to reduce the brittleness of these composites, it was proposed to replace the TiC ceramic phase by the MAX phase of titanium silicon carbide (Ti3SiC2) and use the SHS process to obtain a Ti3SiC2–Ni skeleton composite. Nickel for Ti3SiC2skeleton infiltration was introduced in three variants: by introducing to the reaction mixture; in the form of a briquette located between two SHS charge briquettes; and similar to the second variant, but with the barrier layers of paper between the Ni and SHS charge briquettes. It was shown that Ni melt in all three variants prevents the formation of the titanium silicon carbide MAX phase thus leading to its degradation. Ni introduction into the reaction mixture according to the first variant made it possible to obtain a homogeneous composite, which became almost non-porous with an increase in Ni concentration up to 50 %. When the Ni briquette was placed between two compacted briquettes of SHS charge, it was possible to melt a relatively small amount of Ni (23–29 % of the mass of synthesized composite samples), which was not enough to completely fill the porous layered skeletons of Ti3SiC2. 20 % of Si added to the Ni briquette increased infiltration depth, lowered the degree of MAX phase degradation at the infiltration point, and formed a more homogeneous composite consisting of a porous skeleton of TiC, TiSi2and Ti3SiC2phases partially filled with metallic nickel during Ni(Si) melt infiltration.

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High-Temperature Firing of Composite Based on the Max-Phase of the Ti–Al–C System

Refractories and Industrial Ceramics ◽

10.1007/s11148-018-0144-1 ◽

2018 ◽

Vol 58 (5) ◽

pp. 557-561 ◽

Cited By ~ 5

Author(s):

S. N. Galyshev ◽

P. M. Bazhin ◽

A. M. Stolin ◽

F. F. Musin ◽

P. V. Solov’ev ◽

...

Keyword(s):

High Temperature ◽

Max Phase ◽

Temperature Firing

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Property of mono-vacancy in MAX phase M3AC2 (M=Ti, A=Al, Si, or Ge): First-principles calculations

Modern Physics Letters B ◽

10.1142/s0217984918501609 ◽

2018 ◽

Vol 32 (15) ◽

pp. 1850160 ◽

Cited By ~ 1

Author(s):

L. Chen ◽

G. Duan ◽

X. F. Gao ◽

C. L. Wang

Keyword(s):

High Temperature ◽

First Principles ◽

Radiation Resistance ◽

Atomic Layer ◽

Experimental Results ◽

Max Phase ◽

Vacancy Formation ◽

First Principles Calculations ◽

Density Of State ◽

And Migration

The formation and migration energies of the mono-vacancy in M3AC2 have been investigated using first-principles calculations. The results have shown that M element vacancy formation is the most energetically difficult in M3AC2. The A atomic layer is the most active one. It was also found that the energies of mono-vacancy formation and migration in Ti3AlC2 are higher than that in Ti3SiC2 and Ti3GeC2. Moreover, our calculation of the density of state confirms the conclusion that Ti3AlC2 is the most stable in the selected M3AC2 materials under high-temperature or irradiation environment conditions. These results could provide theoretical insights for the experimental results that Ti3AlC2 has a better radiation resistance than Ti3SiC2 and Ti3GeC2.

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