| Abstract Scope |
External fields can strongly modify densification by altering heat flow, defect transport, interfacial chemistry, and the stress-assisted nucleation of grain-boundary defects. Classical sintering models usually treat grain boundaries as continuously available point-defect sinks, leading to diffusion-limited densification. However, in situ transmission electron microscopy experiments in oxide and metallic systems show that densification can proceed through discrete, intermittent events controlled by the nucleation of climb-mediating grain-boundary disconnections.
This presentation will discuss the importance of nucleation-limited response and the role fields might play in affecting the sintering and interfacial deformation response under such conditions. We connect in situ bicrystal and polycrystalline sintering observations with a hazard-based framework that captures the transition between rare-event densification and classical transport-limited behavior. The results provide insight into when fields accelerate densification by enhancing transport, when they modify interfacial nucleation barriers, and when they destabilize sintering through intermittent strain bursts. |