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In situ study of heavy ion irradiation response of immiscible Cu/Fe multilayers

Journal of Nuclear Materials

Chen, Youxing; Li, Nan; Bufford, Daniel C.; Li, Jin; Hattar, Khalid M.; Wang, Haiyan; Zhang, Xinghang

By providing active defect sinks that capture and annihilate radiation induced defect clusters immiscible metallic multilayers with incoherent interfaces can effectively reduce defect density in ion irradiated metals. Although it is anticipated that defect density within the layers should vary as a function of distance to the layer interface, there is, to date, little in situ TEM evidence to validate this hypothesis. In our study monolithic Cu films and Cu/Fe multilayers with individual layer thickness, h, of 100 and 5 nm were subjected to in situ Cu ion irradiation at room temperature to nominally 1 displacement-per-atom inside a transmission electron microscope. Rapid formation and propagation of defect clusters were observed in monolithic Cu, whereas fewer defects with smaller dimensions were generated in Cu/Fe multilayers with smaller h. Moreover, in situ video shows that the cumulative defect density in Cu/Fe 100 nm multilayers indeed varies, as a function of distance to the layer interfaces, supporting a long postulated hypothesis.

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TYPE Journal Article YEAR 2016
DOIOSTI

Thermal stability comparison of nanocrystalline Fe-based binary alloy pairs

JOM. Journal of the Minerals, Metals & Materials Society

Clark, Blythe C.; Hattar, Khalid M.; Marshall, Michael; Chookajorn, Tonghai; Boyce, Brad L.; Schuh, Christopher A.

Here, the widely recognized property improvements of nanocrystalline (NC) materials have generated significant interest, yet have been difficult to realize in engineering applications due to the propensity for grain growth in these interface-dense systems. While traditional pathways to thermal stabilization can slow the mobility of grain boundaries, recent theories suggest that solute segregation in NC alloy can reduce the grain boundary energy such that thermodynamic stabilization is achieved. Following the predictions of Murdock et al., here we compare for the first time the thermal stability of a predicted NC stable alloy (Fe-10at.% Mg) with a predicted non-NC stable alloy (Fe-10at.% Cu) using the same processing and characterization methodologies. Results indicate improved thermal stability of the Fe-Mg alloy in comparison to the Fe-Cu, and observed microstructures are consistent with those predicted by Monte Carlo simulations.

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TYPE Journal Article YEAR 2016
DOIOSTI
Results 351–375 of 613
Results 351–375 of 613