Investigation on the Effects of Grain Boundary on Deformation Behavior of Bicrystalline Pillar by Crystal Plasticity Finite Element Method

Abstract

A dislocation density–grain boundary interaction scheme coupled with the dislocation density-based crystalline plasticity finite element method has been established and used to investigate the deformation behavior of bicrystalline pillars with the same grain boundary misorientation angle but different crystal orientations. It is found that the angle between the activated slip systems, which is determined by the crystal orientations, rather than the grain boundary misorientation angle, influences the interactions between the plastic slip and the grain boundary, which further influence the heterogeneous deformation of bicrystalline specimens.

Influence of Grain Boundary Morphology on DDC Sensitivity of Nickel Base Alloy Deposited Metal

“…It is considered that the increase of grain size and the decrease of DDC resistance are related to strain concentration at grain boundary during tension. For grain boundary without precipitates, sliding of grain boundary during tension leads to stress concentration and strain localization at trigeminal grain boundary [3,7]. With the increase of grain size, each trigeminal grain boundary needs to bear greater stress concentration and strain.…”

“…On the other hand, small grain size and more curved grain boundary of 305 sample also affects its VoA. Through finite element calculation, Zhou Hui [7] found that the maximum Mises stress of curved grain boundary is reduced and the stress Engineering Materials Research distribution is more uniform than that of straight grain boundary. In terms of macro properties, 305 sample has stronger grain boundary deformation ability and higher VoA than that of 315.…”

“…To VoA of 325 sample higher than that of 305 sample, it may be a result of the comprehensive action of grain boundary and precipitate. STF test found that when there are carbides at the grain boundary, the strain exists not only at the trigeminal crystal boundary, but also at the carbide / matrix interface, thus dispersing the strain at the trigeminal grain boundary [7]. In addition, curved grain boundary can mechanically lock the grain boundary and effectively hinder its sliding [7].…”

“…However, these materials and their welded joints are easy to produce ductility dip cracking (DDC) which seriously threatens the safety of equipment in service. The generation mechanism of DDC mainly includes sulfur segregation and embrittlement [1,2], grain boundary shear and grain boundary slip [3][4][5] and precipitation induced crack [6,7], etc. Factors affecting DDC are complex and numerous, such as precipitated phase, impurity element segregation and grain boundary properties [8,9], etc.…”

Crystal Plasticity (Volume II)

“…Steels and iron-based alloys [2-9]; • Non-ferrous alloys with fcc-(Ni- [10,11] and Cu-based [12][13][14]), or hcp crystal structure (Mg- [15,16] and Ti-based [17,18]). Other examples include Zirconium [19], Bi-Sn alloy [20] or polycarbonate resins [21]; • Multicomponent and high-entropy alloys [22][23][24]; • General theoretical studies on crystal plasticity [25][26][27].…”