We investigated the morphological and crystallographic features of α' martensite variants in Ti-25 at.% Hf and Ti-50 at.% Hf alloys by transmission Kikuchi diffraction and transmission electron microscopy. On the basis of the results, we also discussed the formation process of variants and the self-accommodation. Both alloys, after solution treatment and quenching in ice water, consisted of α' martensite with a hexagonal close-packed structure. The α' martensite exhibited a larger plate-like morphology several micrometers in length, along with a finer morphology with a width of tens of nanometers. The formation of {<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40830_2025_529_Article_IEq1.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="33" /> </InlineMediaObject> <EquationSource Format="TEX">$10\overline{1}1$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>10</mn> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>}α' twins was induced within a larger correspondence variant (CV) as a lattice invariant shear (LIS), and {<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40830_2025_529_Article_IEq2.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="33" /> </InlineMediaObject> <EquationSource Format="TEX">$10\overline{1}1$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>10</mn> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>}α' twins were also the boundaries bounded two neighboring CVs. In formation process of the martensite variants of Ti–Hf alloys, a larger CV with a plate-like morphology is first formed with a {<InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40830_2025_529_Article_IEq3.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="33" /> </InlineMediaObject> <EquationSource Format="TEX">$10\overline{1}1$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>10</mn> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>}α' twin as an LIS in a β parent phase; finer CVs are subsequently generated from the step-like boundary with the {<InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40830_2025_529_Article_IEq4.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="33" /> </InlineMediaObject> <EquationSource Format="TEX">$10\overline{1}1$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>10</mn> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>}α' twin plane, followed by the formation of a pair of CVs with the twin plane to relax the transformation strain.

Morphological and Crystallographic Features of α' Martensite in Binary Ti–Hf Alloy

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发表日期：

2025年2月21日

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M. Matsuda,
S. Ohsumi,
S. Ii

摘要

We investigated the morphological and crystallographic features of α' martensite variants in Ti-25 at.% Hf and Ti-50 at.% Hf alloys by transmission Kikuchi diffraction and transmission electron microscopy. On the basis of the results, we also discussed the formation process of variants and the self-accommodation. Both alloys, after solution treatment and quenching in ice water, consisted of α' martensite with a hexagonal close-packed structure. The α' martensite exhibited a larger plate-like morphology several micrometers in length, along with a finer morphology with a width of tens of nanometers. The formation of { $10\overline{1}1$ $10 \bar{1} 1$ }_α' twins was induced within a larger correspondence variant (CV) as a lattice invariant shear (LIS), and { $10\overline{1}1$ $10 \bar{1} 1$ }_α' twins were also the boundaries bounded two neighboring CVs. In formation process of the martensite variants of Ti–Hf alloys, a larger CV with a plate-like morphology is first formed with a { $10\overline{1}1$ $10 \bar{1} 1$ }_α' twin as an LIS in a β parent phase; finer CVs are subsequently generated from the step-like boundary with the { $10\overline{1}1$ $10 \bar{1} 1$ }_α' twin plane, followed by the formation of a pair of CVs with the twin plane to relax the transformation strain.