Study on shallow grain induced micro-region surface topography instability of bulk Sn alloys upon internal stress conditions

Bulk Sn-alloy surface spontaneously develop topographical changes at room temperature due to the time-varying shallow grain (SG) transformations, significantly impacting surface roughness and arising surface instability concerns for its industrial applications such as fixed abrasive lapping plates....

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Main Authors: Bei Hu, Wenjun Zhou, Kensuke Tsuchiya
Format: Article
Language:English
Published: Elsevier 2025-06-01
Series:Materials & Design
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Online Access:http://www.sciencedirect.com/science/article/pii/S0264127525004915
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author Bei Hu
Wenjun Zhou
Kensuke Tsuchiya
author_facet Bei Hu
Wenjun Zhou
Kensuke Tsuchiya
author_sort Bei Hu
collection DOAJ
description Bulk Sn-alloy surface spontaneously develop topographical changes at room temperature due to the time-varying shallow grain (SG) transformations, significantly impacting surface roughness and arising surface instability concerns for its industrial applications such as fixed abrasive lapping plates. However, the underlying case behind SG formation under different internal stress conditions is less investigated especially in bulk alloys, limiting surface quality control during manufacturing. This work focuses on the internal residual stress induced SG transformations and its resultant surface and microstructural features. Two distinct internal stress conditions were fabricated with industrial standard casting and forging respectively, to create varied subsurface stress fields for elucidating SGs’ behavior. Results reveal that SG formation is highly affected and facilitated by stress distribution via active recrystallization near grain boundaries, resulting in new grain boundaries and dynamic crystallographic reorientations. Cast Sn-1 wt% Bi samples exhibited a more pronounced stress gradient near surface, resulting in a rapid increase in surface peak height around SGs, which conversely credits forging as a better method in suppressing the unwanted surface topographic variation. This work summarizes the fundamental understanding of SG behavior under varying internal stress conditions, elevating the function-oriented manufacturing process design on bulk Sn-alloy for ensuring the surface quality.
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spelling doaj-art-bf656c77a8d942b7b9d8f975d85dd1222025-08-20T03:11:26ZengElsevierMaterials & Design0264-12752025-06-0125411407110.1016/j.matdes.2025.114071Study on shallow grain induced micro-region surface topography instability of bulk Sn alloys upon internal stress conditionsBei Hu0Wenjun Zhou1Kensuke Tsuchiya2Corresponding author.; Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, JapanInstitute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, JapanInstitute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, JapanBulk Sn-alloy surface spontaneously develop topographical changes at room temperature due to the time-varying shallow grain (SG) transformations, significantly impacting surface roughness and arising surface instability concerns for its industrial applications such as fixed abrasive lapping plates. However, the underlying case behind SG formation under different internal stress conditions is less investigated especially in bulk alloys, limiting surface quality control during manufacturing. This work focuses on the internal residual stress induced SG transformations and its resultant surface and microstructural features. Two distinct internal stress conditions were fabricated with industrial standard casting and forging respectively, to create varied subsurface stress fields for elucidating SGs’ behavior. Results reveal that SG formation is highly affected and facilitated by stress distribution via active recrystallization near grain boundaries, resulting in new grain boundaries and dynamic crystallographic reorientations. Cast Sn-1 wt% Bi samples exhibited a more pronounced stress gradient near surface, resulting in a rapid increase in surface peak height around SGs, which conversely credits forging as a better method in suppressing the unwanted surface topographic variation. This work summarizes the fundamental understanding of SG behavior under varying internal stress conditions, elevating the function-oriented manufacturing process design on bulk Sn-alloy for ensuring the surface quality.http://www.sciencedirect.com/science/article/pii/S0264127525004915Sn alloySurface topographic instabilityShallow grainMicrostructure evolutionResidual stress
spellingShingle Bei Hu
Wenjun Zhou
Kensuke Tsuchiya
Study on shallow grain induced micro-region surface topography instability of bulk Sn alloys upon internal stress conditions
Materials & Design
Sn alloy
Surface topographic instability
Shallow grain
Microstructure evolution
Residual stress
title Study on shallow grain induced micro-region surface topography instability of bulk Sn alloys upon internal stress conditions
title_full Study on shallow grain induced micro-region surface topography instability of bulk Sn alloys upon internal stress conditions
title_fullStr Study on shallow grain induced micro-region surface topography instability of bulk Sn alloys upon internal stress conditions
title_full_unstemmed Study on shallow grain induced micro-region surface topography instability of bulk Sn alloys upon internal stress conditions
title_short Study on shallow grain induced micro-region surface topography instability of bulk Sn alloys upon internal stress conditions
title_sort study on shallow grain induced micro region surface topography instability of bulk sn alloys upon internal stress conditions
topic Sn alloy
Surface topographic instability
Shallow grain
Microstructure evolution
Residual stress
url http://www.sciencedirect.com/science/article/pii/S0264127525004915
work_keys_str_mv AT beihu studyonshallowgraininducedmicroregionsurfacetopographyinstabilityofbulksnalloysuponinternalstressconditions
AT wenjunzhou studyonshallowgraininducedmicroregionsurfacetopographyinstabilityofbulksnalloysuponinternalstressconditions
AT kensuketsuchiya studyonshallowgraininducedmicroregionsurfacetopographyinstabilityofbulksnalloysuponinternalstressconditions