The Onset of Abnormal Grain Growth in Al-Ga Polycrystals

Review: grain boundary faceting–roughening phenomena

“…In case of 2D grain growth (each grain has faces on the top and bottom of a plate or film), the difference between quick and slow GBs is only 2.5 [159]. If the mobility spread is between 2.5. and 3.5, the abnormal grains appear when, during the grain growth, the 3D grain structure becomes 2D [160]. What are the reasons of GB mobility difference?…”

“…Similarly, the low melting temperature of the Nb-rich, Ba-poor phase at the GBs caused localized liquid-phase sintering, resulting in abnormal grain growth in the strontium barium niobate Sr 0.6 Ba 0.4 Nb 2 O 6 ceramics or lead zirconate titanate [166,167]. Accumulation of impurities in GBs also leads to the formation of GB liquid films and to increase of mobility of certain GBs [160,[168][169][170]. In this review, it is interesting for us to investigate how the GB faceting-roughening influences the transition from normal to abnormal grain growth.…”

“…If all GBs have a rough structure, then a nearly isotropic normal grain growth occurs. The abnormal grain growth is observed to occur when all or a fraction of the GBs are faceted [126,160,[173][174][175][176][177][178][179][180][181][182][183][184]. Below follows the detailed discussion of the works [126,160,[173][174][175][176][177][178][179][180][181][182][183][184].…”

Influence of the Grain Boundary Phase Transitions on the Diffusion-Related Properties

“…All processes which can change the properties of GBs and IBs affect drastically the behaviour of polycrystalline metals and ceramics [1]. GB phase transitions are one of the important examples of such processes [2]. Recently, the lines of GB phase transitions began to appear in the traditional bulk phase diagrams [2][3][4][5][6][7].…”

“…GB phase transitions are one of the important examples of such processes [2]. Recently, the lines of GB phase transitions began to appear in the traditional bulk phase diagrams [2][3][4][5][6][7]. The addition of these equilibrium lines to the bulk phase diagrams ensures an adequate description of polycrystalline materials.…”