Interfacial strain relief by periodic dislocation doublets emerging from rotationally related orientation relationships of Y4Zr3O12 dispersions in ferrite matrix

Abstract

The trigonal/bcc orientation relationships (ORs) and their likelihood of occurrence are extensively studied using dispersed Y 4 Zr 3 O 12 (δ) nano-precipitates in bcc Fe (α) matrix by means of transmission electron microscopy, image simulations and a crystallographic model. Two orientation relationships related by a rotation:[1 20] δ ||[111] α with (21 2) δ ||( 110) α and [1 20] δ ||[111] α with (00 3) δ ||( 110) α , are established and periodic arrays of misfit dislocation doublets are identified at the strained interface in (110) α for both ORs. Further eighteen energetically feasible ORs in Y 4 Zr 3 O 12 /bcc system are deduced by combining stereographic projections, which include the two predominant ORs in this study and other ORs in literature. The orientation relationship which generates interface with a minimum number of dislocation doublets is the most frequent.

Experimental validation of density functional theory calculations on the Zr/Al oxide nanocluster formation in bcc Fe

“…Nearly 74% of the precipitates in the replica possess phase contrast of Figure 3(a) and power spectrum similar to Figure 3(b), which can be indexed for < 1 20 > or < 2 10 > directions of Y 4 Zr 3 O 12 shown in Figure 3(d). Earlier multislice simulations indicated that the < 1 20 > δ produces 'spot-like' contrast in HRTEM images and < 2 10 > δ is characterized by a 'line like' contrast [18]. The contrast observed in the current study is exactly similar to the contrast of < 1 20 > δ ,as superimposed in the Bragg filtered image Figure 3(d).…”