Analysis of variant selection in friction-stir-processed high-strength low-alloy steels

作者：Abbasi Majid^*; Nelson Tracy W; Sorensen Carl D

来源：Journal of Applied Crystallography, 2013, 46(3): 716-725.

DOI：10.1107/S0021889813008522

Variant selection in friction-stir-welded high-strength low-alloy steels has been studied using the electron backscatter diffraction and prior austenite (PA) reconstruction techniques described in previous papers. A hypothesis for variant selection has been proposed based on grain-boundary interfacial energy and misorientation. This study focuses on austenite %26lt; 111 %26gt; boundaries with a two-dimensional approach. Results indicate that variant selection is strongly dependent on misorientation. Certain PA misorientations produce combinations of variants that minimize the interfacial energies between a ferrite nucleus and a neighboring austenite grain, and between adjoining ferrite nuclei along the boundary between two PA grains. PA grains that exhibit a 60 degrees %26lt; 111 %26gt; misorientation between them satisfy both these conditions for a combination of variants. These PA boundaries exhibit strong variant selection. As a result, the density of these boundary types influences the overall variant selection. Additionally, variant selection is more prevalent in small PA grains (%26lt;150 mu m), which is probably a result of limited intragranular nucleation. Nearly all variants are present in larger PA grains.

• 出版日期2013-6