The Grain-Boundary Diffusion of Zn in α-Fe

Abstract

Using semi-infinite amounts of pure Zn and pure Fe as the diffusing media and maintaining constant boundary conditions, the diffusion of Zn into aFe has been experimentally studied at temperatures of 400, 500, and 725°C. Long diffusion times (4 days) were used to allow the various intermetallic phases to become well developed. It was determined that diffusion of Zn into Fe is not ''anomalously rapid,'' but follows normal diffusion behavior for polycrystalline metals in that both lattice diffusion and grain-boundary diffusion contribute to mass transport for the temperatures investigated. The grain-boundary diffusion coefficients determined are consistent with those for many other metal systems.

Interfacial Characterization of Dissimilar Joints Between Al/Mg/Al-Trilayered Clad Sheet to High-Strength Low-Alloy Steel

“…In contrast, the HSLA steel still remained hard enough to prevent the diffusion of Zn into iron since the interface temperature was far below its melting point ($1538°C). Indeed, the normal lattice diffusivity of Zn in a-Fe was reported to be 4.5 9 10 À24 m 2 /s at 400°C, 40 which was substantially lower that of Zn in Al (1.208 9 10 À17 m 2 /s) 38 at 240°C.…”

Interstitial Segregation has the Potential to Mitigate Liquid Metal Embrittlement in Iron

“…[ 24 ] The asymmetric segregation profiles of B and C indicate that the GB has migrated during the annealing treatment either induced by Zn segregation [ 2,36 ] or through the triple line, where the GB is connected to the liquid Zn reservoir. [ 37 ] Our experimental observation of the GB structure show locally asymmetric segments with (430)/(410) and (010)/(110) facets. However, their structure is primarily composed of the symmetric Σ5 (310) as well as Σ5 (310) kite‐type structural units of the GBs.…”

Ultrasonic Spot Welding of Similar and Dissimilar Alloys for Automotive Applications

“…It should be noted that the growth of the interface diffusion layer was always towards Al side after a continuous layer was formed. This could be attributed to several reasons including, much closer melting point of Zn (419.6C) to that of Al (660.4C) compared to that of Fe (1538C); smaller atomic radius of Zn (0.133 nm) than that of Al (0.143 nm) but larger than that of Fe (0.124 nm); and much higher lattice diffusivity of Zn in Al (1.208 × 10 -17 m 2 /s) at 240C than that of Zn in Fe (4.5 × 10 -24 m 2 /s) even at 400C [162,163]. researchers also observed a similar squeezing effect during USW of Al to steel [27,37].…”