Title: Texture Memory in Hexagonal Metals and Its Mechanism

Abstract

Texture memory is a phenomenon in which retention of initial textures occurs after a complete cycle of forward and backward transformations, and it occurs in various phase-transforming materials including cubic and hexagonal metals such as steels and Ti and Zr alloys. Texture memory is known to be caused by the phenomena called variant selection, in which some of the allowed child orientations in an orientation relationship between the parent and child phases are preferentially selected. Without such variant selection, the phase transformations would randomize preferred orientations. In this article, the methods of prediction of texture memory and mechanisms of variant selections in hexagonal metals are explored. The prediction method using harmonic expansion of orientation distribution functions with the variant selection in which the Burgers orientation relationship, {110}β//{0001}_α-hex <1$$\bar{1}$$1>β//$$\langle2\bar{11}0\rangle$$_α-hex, is held with two or more adjacent parent grains at the same time, called “double Burgers orientation relation (DBOR)”, is introduced. This method is shown to be a powerful tool by which to analyze texture memory and ultimately provide predictive capabilities for texture changes during phase transformations. Variation in nucleation and growth rates on special boundaries and an extensive growth of selected variants are also described. Analysis of textures of commercially pure Ti observed in situ by pulsed neutron diffraction reveals that the texture memory in CP-Ti is indeed quite well predicted by consideration of the mechanism of DBOR. The analysis also suggests that the nucleation and growth rates on the special boundary of 90° rotation about $$\langle2\bar{11}0\rangle$$_α-hex should be about three times larger than those of the other special boundaries, and the selected variants should grow extensively into not only one parent grain but also other grains in α-hex(hexagonal)→β(bcc) transformation. The model calculations of texture development during two consecutive cycles of α-hex→β→α-hex transformation in CP-Ti and Zr are also shown.

Authors:

Tomida, Toshiro ^[1]; Vogel, Sven C.  ^[2];

• Search DOE PAGES for author "Vogel, Sven C."
• Search DOE PAGES for ORCID "0000-0003-2049-0361"

Onuki, Yusuke  ^[1];

• Search DOE PAGES for author "Onuki, Yusuke"
• Search DOE PAGES for ORCID "0000-0001-9763-0970"

Sato, Shigeo  ^[1]

• Search DOE PAGES for author "Sato, Shigeo"
• Search DOE PAGES for ORCID "0000-0003-3294-3348"

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+ Show Author Affiliations

1. Ibaraki Univ., (Japan)
2. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Publication Date:

Mon Oct 18 00:00:00 EDT 2021

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States). Los Alamos Neutron Science Center (LANSCE)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1983125

Grant/Contract Number:  

89233218CNA000001

Resource Type:

Accepted Manuscript

Journal Name:

Metals

Additional Journal Information:

Journal Volume: 11; Journal Issue: 10; Journal ID: ISSN 2075-4701

Publisher:

MDPI

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; texture memory; transformation texture; cubic; hexagonal; steel; titanium; zirconium