At present,the emerging solid-phase friction-based additive manufacturing technology,including friction rolling additive man-ufacturing(FRAM),can only manufacture simple single-pass components.In this study,multi-laye...At present,the emerging solid-phase friction-based additive manufacturing technology,including friction rolling additive man-ufacturing(FRAM),can only manufacture simple single-pass components.In this study,multi-layer multi-pass FRAM-deposited alumin-um alloy samples were successfully prepared using a non-shoulder tool head.The material flow behavior and microstructure of the over-lapped zone between adjacent layers and passes during multi-layer multi-pass FRAM deposition were studied using the hybrid 6061 and 5052 aluminum alloys.The results showed that a mechanical interlocking structure was formed between the adjacent layers and the adja-cent passes in the overlapped center area.Repeated friction and rolling of the tool head led to different degrees of lateral flow and plastic deformation of the materials in the overlapped zone,which made the recrystallization degree in the left and right edge zones of the over-lapped zone the highest,followed by the overlapped center zone and the non-overlapped zone.The tensile strength of the overlapped zone exceeded 90%of that of the single-pass deposition sample.It is proved that although there are uneven grooves on the surface of the over-lapping area during multi-layer and multi-pass deposition,they can be filled by the flow of materials during the deposition of the next lay-er,thus ensuring the dense microstructure and excellent mechanical properties of the overlapping area.The multi-layer multi-pass FRAM deposition overcomes the limitation of deposition width and lays the foundation for the future deposition of large-scale high-performance components.展开更多
AZ31 magnesium alloy was used as the object of study to fabricate an alloy with the bimodal grain structure using singlepass hot rolling,and to explore how this structure enhances the strength and plasticity of the al...AZ31 magnesium alloy was used as the object of study to fabricate an alloy with the bimodal grain structure using singlepass hot rolling,and to explore how this structure enhances the strength and plasticity of the alloy.The results show that the formation of the bimodal grain structure is more pronounced at rolling temperatures ranging from 350°C to 450°C,especially under conditions of large reduction(≥40%).The optimized proportion and distribution of the bimodal grain structure play a pivotal role in simultaneously enhancing the strength and ductility of the alloy,significantly impacting the mechanical properties.The rolled sheet with the bimodal grain structure achieves an ultimate tensile strength of 258.3 MPa and an elongation of 17.1%under a rolling reduction of 40%with the rolling rate of 75 m/min and rolling temperature of 400°C.Adjusting rolling parameters,including temperature,reduction ratio and rolling rate,is crucial for optimizing the bimodal grain structure,thereby achieving a balance between plasticity improvement and high strength maintenance.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFB3404700)the National Natural Science Foundation of China(Nos.52105313 and 52275299)+2 种基金the Research and Development Program of Beijing Municipal Education Commission,China(No.KM202210005036)the Natural Science Foundation of Chongqing,China(No.CSTB2023NSCQ-MSX0701)the National Defense Basic Research Projects of China(No.JCKY2022405C002).
文摘At present,the emerging solid-phase friction-based additive manufacturing technology,including friction rolling additive man-ufacturing(FRAM),can only manufacture simple single-pass components.In this study,multi-layer multi-pass FRAM-deposited alumin-um alloy samples were successfully prepared using a non-shoulder tool head.The material flow behavior and microstructure of the over-lapped zone between adjacent layers and passes during multi-layer multi-pass FRAM deposition were studied using the hybrid 6061 and 5052 aluminum alloys.The results showed that a mechanical interlocking structure was formed between the adjacent layers and the adja-cent passes in the overlapped center area.Repeated friction and rolling of the tool head led to different degrees of lateral flow and plastic deformation of the materials in the overlapped zone,which made the recrystallization degree in the left and right edge zones of the over-lapped zone the highest,followed by the overlapped center zone and the non-overlapped zone.The tensile strength of the overlapped zone exceeded 90%of that of the single-pass deposition sample.It is proved that although there are uneven grooves on the surface of the over-lapping area during multi-layer and multi-pass deposition,they can be filled by the flow of materials during the deposition of the next lay-er,thus ensuring the dense microstructure and excellent mechanical properties of the overlapping area.The multi-layer multi-pass FRAM deposition overcomes the limitation of deposition width and lays the foundation for the future deposition of large-scale high-performance components.
基金Corresponding author:Jiang Haitao,Ph.D.,Professor,Institute of Engineering Technology,University of Science and Technology Beijing,Beijing 102206,P.R.China,Tel:0086-10-62332598,E-mail:jianght@ustb.edu.cn。
文摘AZ31 magnesium alloy was used as the object of study to fabricate an alloy with the bimodal grain structure using singlepass hot rolling,and to explore how this structure enhances the strength and plasticity of the alloy.The results show that the formation of the bimodal grain structure is more pronounced at rolling temperatures ranging from 350°C to 450°C,especially under conditions of large reduction(≥40%).The optimized proportion and distribution of the bimodal grain structure play a pivotal role in simultaneously enhancing the strength and ductility of the alloy,significantly impacting the mechanical properties.The rolled sheet with the bimodal grain structure achieves an ultimate tensile strength of 258.3 MPa and an elongation of 17.1%under a rolling reduction of 40%with the rolling rate of 75 m/min and rolling temperature of 400°C.Adjusting rolling parameters,including temperature,reduction ratio and rolling rate,is crucial for optimizing the bimodal grain structure,thereby achieving a balance between plasticity improvement and high strength maintenance.
