Precipitation strengthening is a common way to strengthen metallic materials, where the effectiveness depends on the morphology, size, fraction of the precipitates, etc. The precipitation process is significantly influenced by crystal defects like dislocations and grain boundaries, which act as nucleation sites. However, the understanding of the transformation crystallography at interphase boundaries is limited. In this study, the precipitation crystallography of α phase on the stress-induced martensite in Ti–16V–4Sn was studied by scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). Stress-induced α″ martensite is produced by uniaxial compression of solution-treated alloy and maintains an orientation relationship with the β matrix (βM), i.e., <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10853_2025_10810_Article_IEq1.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="259" /> </InlineMediaObject> <EquationSource Format="TEX">$\left( {110} \right)_{\beta } //\left( {001} \right)_{{\alpha^{\prime \prime } }} ,\left[ {1 - 10} \right]_{\beta } //\left[ {100} \right]_{{\alpha^{\prime \prime } }}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mfenced close=")" open="("> <mn>110</mn> </mfenced> <mi>β</mi> </msub> <mo stretchy="false">/</mo> <mo stretchy="false">/</mo> <msub> <mfenced close=")" open="("> <mn>001</mn> </mfenced> <msup> <mi>α</mi> <mo>″</mo> </msup> </msub> <mo>,</mo> <msub> <mfenced close="]" open="["> <mrow> <mn>1</mn> <mo>-</mo> <mn>10</mn> </mrow> </mfenced> <mi>β</mi> </msub> <mo stretchy="false">/</mo> <mo stretchy="false">/</mo> <msub> <mfenced close="]" open="["> <mn>100</mn> </mfenced> <msup> <mi>α</mi> <mo>″</mo> </msup> </msub> </mrow> </math></EquationSource> </InlineEquation> or <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10853_2025_10810_Article_IEq2.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="268" /> </InlineMediaObject> <EquationSource Format="TEX">$\left( {110} \right)_{\beta } // \, \left( {001} \right)_{{\alpha^{{^{\prime \prime } }} }} , \, \left[ {1 - 10} \right]_{\beta } // \, \left[ {110} \right]_{{\alpha^{{^{\prime \prime } }} }}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mfenced close=")" open="("> <mn>110</mn> </mfenced> <mi>β</mi> </msub> <mo stretchy="false">/</mo> <mo stretchy="false">/</mo> <mspace width="0.166667em" /> <mmultiscripts> <mfenced close=")" open="("> <mn>001</mn> </mfenced> <mmultiscripts> <mi>α</mi> <mrow /> <mmultiscripts> <mrow /> <mrow /> <mo>″</mo> </mmultiscripts> </mmultiscripts> <mrow /> </mmultiscripts> <mo>,</mo> <mspace width="0.166667em" /> <msub> <mfenced close="]" open="["> <mrow> <mn>1</mn> <mo>-</mo> <mn>10</mn> </mrow> </mfenced> <mi>β</mi> </msub> <mo stretchy="false">/</mo> <mo stretchy="false">/</mo> <mspace width="0.166667em" /> <mmultiscripts> <mfenced close="]" open="["> <mn>110</mn> </mfenced> <mmultiscripts> <mi>α</mi> <mrow /> <mmultiscripts> <mrow /> <mrow /> <mo>″</mo> </mmultiscripts> </mmultiscripts> <mrow /> </mmultiscripts> </mrow> </math></EquationSource> </InlineEquation>. Subsequent aging resulted in a sandwich-like microstructure (βM–α–βT), where the film-like α phase precipitated on the boundary of martensite continuously, and the martensite reversed to β phase (βT) before α precipitation, which held the orientation of 50–60°/<110> with βM. The precipitated α on the martensite boundary held Burgers orientation relationship (BOR), i.e., (110)β // (0001)α, [1–11]β // [11–20]α with both βM and inside βT, respectively. The observed misorientation angle of 50°–60° and the transformation crystallography of α phase are rationalized by transformed variants. Graphical abstract

Study on the transformation crystallography of decomposed martensite in Ti–16V–4Sn

期刊论文
发表日期：

2025年4月1日

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Tong Wang,
Ping Yang,
Xinfu Gu

摘要

Precipitation strengthening is a common way to strengthen metallic materials, where the effectiveness depends on the morphology, size, fraction of the precipitates, etc. The precipitation process is significantly influenced by crystal defects like dislocations and grain boundaries, which act as nucleation sites. However, the understanding of the transformation crystallography at interphase boundaries is limited. In this study, the precipitation crystallography of α phase on the stress-induced martensite in Ti–16V–4Sn was studied by scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). Stress-induced α″ martensite is produced by uniaxial compression of solution-treated alloy and maintains an orientation relationship with the β matrix (β_M), i.e., $\left( {110} \right)_{\beta } //\left( {001} \right)_{{\alpha^{\prime \prime } }} ,\left[ {1 - 10} \right]_{\beta } //\left[ {100} \right]_{{\alpha^{\prime \prime } }}$ ${(110)}_{β} / / {(001)}_{α^{″}}, {[1 - 10]}_{β} / / {[100]}_{α^{″}}$ or $\left( {110} \right)_{\beta } // \, \left( {001} \right)_{{\alpha^{{^{\prime \prime } }} }} , \, \left[ {1 - 10} \right]_{\beta } // \, \left[ {110} \right]_{{\alpha^{{^{\prime \prime } }} }}$ ${(110)}_{β} / / {(001)}_{α^{^{″}}}, {[1 - 10]}_{β} / / {[110]}_{α^{^{″}}}$ . Subsequent aging resulted in a sandwich-like microstructure (β_M–α–β_T), where the film-like α phase precipitated on the boundary of martensite continuously, and the martensite reversed to β phase (β_T) before α precipitation, which held the orientation of 50–60°/<110> with β_M. The precipitated α on the martensite boundary held Burgers orientation relationship (BOR), i.e., (110)_β // (0001)_α, [1–11]_β // [11–20]_α with both β_M and inside β_T, respectively. The observed misorientation angle of 50°–60° and the transformation crystallography of α phase are rationalized by transformed variants.

Graphical abstract