What is the diffusion coefficient of nitrogen in austenite and ferrite in steel?
Best insight from top research papers
The diffusion coefficient of nitrogen in austenite and ferrite in steel is influenced by various factors such as temperature, nitrogen supply rate, and the presence of other elements. The diffusion behavior of nitrogen in steel is affected by hydrogen and nitrogen concentration, as well as the stress induced by interstitial solutes atoms expanding the lattice of the alloy . The activation energy for nitrogen diffusion in both austenitic stainless steels and CoCr alloys is approximately 0.8 eV . The diffusion of nitrogen in (Fe,Co,Ni)CrN alloys is characterized by fast diffusion with an activation energy of 0.8-1.0 eV . In duplex stainless steels, the diffusion coefficients of nitrogen in both austenite and ferrite phases appear to be similar . The thickness of the nitrogen diffusion layer in the alpha phase is greater than in the gamma phase .
Answers from top 4 papers
More filters
| Papers (4) | Insight |
|---|---|
15 Citations | The provided paper does not mention the diffusion coefficient of nitrogen in austenite and ferrite in steel. |
| The provided paper does not mention the diffusion coefficient of nitrogen in austenite and ferrite in steel. | |
| The diffusion coefficients of nitrogen in austenite and ferrite in the steel are not explicitly mentioned in the provided paper. | |
7 Citations | The provided paper does not mention the diffusion coefficient of nitrogen in austenite and ferrite in steel. |
Related Questions
What are the effects of alloying elements on the diffusivity of carbon in iron and steels?4 answersAlloying elements significantly influence the diffusivity of carbon in iron and steels. The presence of defects, such as substitutional alloying elements and edge dislocations, can modify the diffusivity of interstitial solutes like carbon in metals, affecting the overall diffusion process. In the case of steel, the content of elements like Si, Al, and Mn can impact the secondary dendrite arm spacing (SDAS) and the average grain size of the equiaxed crystal zone, ultimately affecting the diffusion behavior of carbon. Additionally, alloying elements like Ti, V, Nb, and Mo have been shown to co-segregate with carbon in α-iron, influencing the grain boundary segregation behavior and potentially forming metal carbides. These findings highlight the intricate interplay between alloying elements and the diffusivity of carbon in iron and steels.
How does niobium contribute to cooling rate of ferritic stainless steel?4 answersNiobium content in ferritic stainless steel contributes to the cooling rate. Increasing the niobium content or the cooling rate leads to a decrease in the ferrite and bainite start temperatures (Ar3, Bs). Additionally, niobium promotes the formation of longer and narrower bainitic ferrite laths and a decrease in polygonal ferrite grain size. The addition of niobium also influences the dendritic growth kinetics, resulting in an increased equiaxed zone ratio (EZR). The EZR significantly increases when 0.7 wt pct of niobium is added to the ferritic stainless steel. The increased EZR is attributed to the larger undercooling at the dendrite tip, providing favorable nucleation conditions for the formation of ferritic stainless steel.
How nitrogen works in ductile iron?5 answersNitrogen in ductile iron works by influencing its mechanical and corrosion properties, as well as its structure. Small additions of nitrogen lead to the formation of complex carbide-nitrides containing magnesium and silicon, which affect the graphite diameter distribution, nodule count, and ferrite fraction. Nitrogen also improves the chemical homogeneity of solid solutions by preventing clustering and enhancing the mobility of interfaces, resulting in a higher level of damping and improved mechanical and corrosion properties. The alloying of iron with nitrogen enhances the metallic component of interatomic bonds and provides a more homogeneous distribution of substitutional solutes through short-range ordering of nitrogen atoms and strong chemical interaction with alloying elements, leading to the high thermodynamic stability of nitrogen austenitic steels. Overall, nitrogen plays a crucial role in enhancing the properties and structure of ductile iron.
How temperature affect diffusion?3 answersTemperature has a significant impact on diffusion. In some cases, as temperature increases, the diffusion coefficient also increases, leading to faster diffusion. However, there are situations where the diffusion coefficient decreases with increasing temperature within a specific temperature range. This behavior can be attributed to the interplay between deterministic dynamics and thermal fluctuations, as well as the mean residence time of particles in different trajectories. Additionally, studies have shown that the diffusion coefficient of wheat moisturization varies over a wide range with temperature, following the Arrhenius equation. Furthermore, it has been observed that unstable diffusion tends to become more stable at higher temperatures, while a decrease in temperature in a stable system can lead to the formation of convective flows and a transition to an unstable state.
Why are P and K transported primarily by diffusion?2 answersP and K are primarily transported by diffusion because diffusion is a process by which matter is transported as a result of random molecular motion. If a substance is not distributed homogeneously in a system, there is a net transfer of that substance in the direction of lower concentration. Diffusion represents an average velocity component of molecules of a particular constituent relative to a fixed frame of reference external to the solution. Advection, on the other hand, is defined as transport responding to a pressure gradient or body force. Advection and diffusion contribute independently to the total transport. Therefore, P and K are primarily transported by diffusion because it allows for the movement of these substances from areas of higher concentration to areas of lower concentration, ensuring their distribution throughout the system.
Is ammonia compatible with 9% nickel steel?5 answersAmmonia is not mentioned in any of the provided abstracts.