Mechanical properties of nitrided niobium alloys

Lakhtin, Yu. M.; Kogan, Ya. D.; Bobok, A.N.; Захарова, Г. В.; Abashin, A. G.

doi:10.1007/bf00656061

Cited by 1 publication

(5 citation statements)

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“…The elastic limit with increasing nitriding time increases by 3...5 times. With increasing nitriding temperature, the value of the tensile strength monotonically increases by 1,5...2,0 times, and the value of the relative elongation decreases monotonically when tested at room temperature [36].…”

Section: Problem Statusmentioning

confidence: 91%

“…The tensile strength of pure niobium increases by 25...30 % at 800 ºC and has almost no effect on heat resistance at 1000 ºC. And for the alloy VN-3 tests for creep and long-term strength at 900...1400 °C showed an increase in the time to failure and improve the characteristics of creep resistance by 1,3...2,5 times do not lead to a decrease in ductility [36].…”

Section: Problem Statusmentioning

confidence: 93%

“…The increase in heat resistance is associated with coherent dispersed nitride phases released in the grain volume and at their boundaries, as well as in the form of individual chains at the boundaries of the blocks. The composition of the selection is defined as nitride Nb and Zr [36].…”

Section: Problem Statusmentioning

confidence: 99%

“…A significant disadvantage of nitriding niobium alloys is the increase in the fragility of the diffusion layers [36]. One of the reasons for the fragility of the alloy at room temperature after nitriding is the segregation of gaseous impurities at the grain boundary and in the boundary volumes, which causes increased microhardness of the boundaries.…”

Section: Problem Statusmentioning

confidence: 99%

“…One of the reasons for the fragility of nitrided Nballoy may be treatment with ammonia [19]. Set nitriding modes that provide the optimal combination of propertyes [36].…”

Section: Problem Statusmentioning

confidence: 99%

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Heat protective coatings on niobium alloys

Babak

Lyashenko

Щепетов

et al. 2020

Mechanics and Advanced Technologies

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The article shows that during plasma-diffusion deposition, a multilayer coating was formed on the surface of the niobium alloy. A highly porous plasma-sprayed layer of molybdenum silicide has a significant spread in thickness (h=100...350 μm, Hμ20=6880 MPa). When studying the microstructure of samples with a plasma-diffusion coating after testing, it was found that cracks in the coating originate in the process of creep, mostly at the interface between the plasma and diffusion layers of the coating. The source of their origin is individual discontinuities in the diffusion layer as delivered. Crack propagation occurs both into the plasma and diffusion layers of the coating. Crack growth in the plasma layer is inhibited due to the rounded nature of the pores and the increased plasticity of this layer. The growth of cracks deep into the sample is, as a rule, inhibited by a boride sublayer. The advantage of plasma-diffusion technology provided an increased plasticity of the coating, the presence of thin barrier sublayers, a discontinuous coating structure, the presence of low-melting compounds that contribute to the healing of defects in the coating, an increase in its corrosion resistance and resistance to thermal fatigue destruction. The combination of these properties made it possible to provide an increase in durability compared to silicide and borosilicide coatings under conditions of isothermal creep in air (1400 °C, 50 MPa) 1.9...3.7 times and under conditions of thermal cyclic creep (1400-250 °C, 50 MPa) in 6.8...8.5 times. It has been determined that the use of a discrete structure will increase the thickness of the coating layer and ensure an increase in their working properties.

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Section: Problem Statusmentioning

confidence: 91%

Section: Problem Statusmentioning

confidence: 93%

Section: Problem Statusmentioning

confidence: 99%

Section: Problem Statusmentioning

confidence: 99%

“…One of the reasons for the fragility of nitrided Nballoy may be treatment with ammonia [19]. Set nitriding modes that provide the optimal combination of propertyes [36].…”

Section: Problem Statusmentioning

confidence: 99%

See 3 more Smart Citations