A new mechanism for field-assisted processing and flash sintering of materials

A unified mechanism for field-assisted phenomena such as enhanced rapid flash sintering, reduction in flow stress and grain growth retardation is proposed. It is argued that defect segregation causes enhanced ionic and electronic transport along dislocations and grain boundaries, which leads to enhanced mobility of dislocations and their selective Joule heating. This selective heating, if uncontrolled, can lead to an avalanche and selective melting of grain boundaries, which is proposed to be the primary mechanism for flash sintering of oxides.