<p>Solid-state additive manufacturing (AM) processes such as multi-layer friction surfacing (MLFS) can overcome typical disadvantages of fusion-based AM such as high residual stresses, porosity or hot cracking. The tool-less process setup of MLFS prevents contamination of the resulting components, e.g., caused by wear or the use of lubricants. The present study investigates MLFS for the precipitation-hardenable alloy AA2024-T3 using a process parameter that yields a high build rate relevant for industrial applications. The fatigue performance is shown and the microstructural and the mechanical anisotropy is examined. The fatigue properties in deposition direction show a high cycle fatigue limit of 170.5 MPa and a decrease in the maximum stress level compared to the base material due to precipitate overageing. The microstructure shows a Brass<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40964_2025_969_Article_IEq1.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="84" /> </InlineMediaObject> <EquationSource Format="TEX">$\{011\}\langle 211\rangle$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo stretchy="false">{</mo> <mn>011</mn> <mo stretchy="false">}</mo> <mo stretchy="false">⟨</mo> <mn>211</mn> <mo stretchy="false">⟩</mo> </mrow> </math></EquationSource> </InlineEquation> texture at the bottom of the layers due to the application of high axial forces. In the center of the layer, no preferred texture was observed, while <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40964_2025_969_Article_IEq2.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="94" /> </InlineMediaObject> <EquationSource Format="TEX">$\text {B}\{\bar{1}12\}\langle 110\rangle$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mtext>B</mtext> <mo stretchy="false">{</mo> <mover accent="true"> <mrow> <mn>1</mn> </mrow> <mrow> <mo stretchy="false">¯</mo> </mrow> </mover> <mn>12</mn> <mo stretchy="false">}</mo> <mo stretchy="false">⟨</mo> <mn>110</mn> <mo stretchy="false">⟩</mo> </mrow> </math></EquationSource> </InlineEquation>/<InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="40964_2025_969_Article_IEq3.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="94" /> </InlineMediaObject> <EquationSource Format="TEX">$\bar{\text {B}}\{1\bar{1}\bar{2}\}\langle \bar{1}\bar{1}0\rangle$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mover accent="true"> <mrow> <mtext>B</mtext> </mrow> <mrow> <mo stretchy="false">¯</mo> </mrow> </mover> <mo stretchy="false">{</mo> <mn>1</mn> <mover accent="true"> <mrow> <mn>1</mn> </mrow> <mrow> <mo stretchy="false">¯</mo> </mrow> </mover> <mover accent="true"> <mrow> <mn>2</mn> </mrow> <mrow> <mo stretchy="false">¯</mo> </mrow> </mover> <mo stretchy="false">}</mo> <mo stretchy="false">⟨</mo> <mover accent="true"> <mrow> <mn>1</mn> </mrow> <mrow> <mo stretchy="false">¯</mo> </mrow> </mover> <mover accent="true"> <mrow> <mn>1</mn> </mrow> <mrow> <mo stretchy="false">¯</mo> </mrow> </mover> <mn>0</mn> <mo stretchy="false">⟩</mo> </mrow> </math></EquationSource> </InlineEquation> shear textures were observed at the top part of the deposited layers. An elongated grain morphology with aspect ratios above 2 is present over the entire layer height. These microstructural characteristics cause anisotropy in mechanical properties, with highest ultimate tensile strength and elongation in deposition direction, i.e., 408 ± 5 MPa and 18 ± 3 % respectively, and the lowest values along the build direction, i.e., 377 ± 21 MPa and 9 ± 3 % respectively. The observed behavior is of considerable importance for the industrial design and application of components manufactured with MLFS as they show that MLFS can also result in anisotropic material properties, depending on the chosen process parameters. It requires careful selection of the right combination of stud material and process parameters to achieve isotropic properties in the deposited structure.</p>

Mechanical behavior, microstructural evolution and texture analysis of AA2024-T351 processed by multi-layer friction surfacing with high build rates

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2025年1月29日

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Marius Hoffmann,
Arne Roos,
Benjamin Klusemann

摘要

Solid-state additive manufacturing (AM) processes such as multi-layer friction surfacing (MLFS) can overcome typical disadvantages of fusion-based AM such as high residual stresses, porosity or hot cracking. The tool-less process setup of MLFS prevents contamination of the resulting components, e.g., caused by wear or the use of lubricants. The present study investigates MLFS for the precipitation-hardenable alloy AA2024-T3 using a process parameter that yields a high build rate relevant for industrial applications. The fatigue performance is shown and the microstructural and the mechanical anisotropy is examined. The fatigue properties in deposition direction show a high cycle fatigue limit of 170.5 MPa and a decrease in the maximum stress level compared to the base material due to precipitate overageing. The microstructure shows a Brass $\{011\}\langle 211\rangle$ ${011} ⟨ 211 ⟩$ texture at the bottom of the layers due to the application of high axial forces. In the center of the layer, no preferred texture was observed, while $\text {B}\{\bar{1}12\}\langle 110\rangle$ $B {\bar{1} 12} ⟨ 110 ⟩$ / $\bar{\text {B}}\{1\bar{1}\bar{2}\}\langle \bar{1}\bar{1}0\rangle$ $\bar{B} {1 \bar{1} \bar{2}} ⟨ \bar{1} \bar{1} 0 ⟩$ shear textures were observed at the top part of the deposited layers. An elongated grain morphology with aspect ratios above 2 is present over the entire layer height. These microstructural characteristics cause anisotropy in mechanical properties, with highest ultimate tensile strength and elongation in deposition direction, i.e., 408 ± 5 MPa and 18 ± 3 % respectively, and the lowest values along the build direction, i.e., 377 ± 21 MPa and 9 ± 3 % respectively. The observed behavior is of considerable importance for the industrial design and application of components manufactured with MLFS as they show that MLFS can also result in anisotropic material properties, depending on the chosen process parameters. It requires careful selection of the right combination of stud material and process parameters to achieve isotropic properties in the deposited structure.