X. Zhang, H. Luo, Y. Wang, B. Jiang, Z. Ji, J. Lui
{"title":"Microstructure prediction of semi-solid AZ91D magnesium alloy prepared by mechanical stirring based on regression analysis and neural network","authors":"X. Zhang, H. Luo, Y. Wang, B. Jiang, Z. Ji, J. Lui","doi":"10.1002/mawe.202400134","DOIUrl":"https://doi.org/10.1002/mawe.202400134","url":null,"abstract":"<p>In the present investigation two smart prediction tools, namely the multiple regression analysis and general regression neural network models were developed to predict average grain size and shape factor of the semi-solid AZ91D magnesium alloy microstructure prepared by mechanical stirring. The process parameters (stirring temperature, stirring rate, stirring time) were considered as input variables to establish predictive models. The models were developed using the multiple regression analysis was employed to determine the significance of process parameters on microstructure. In the general regression neural network models, the k-fold cross validation method is used to optimize the smoothing factor. The neural network models were trained, validated and tested. The results show the general regression neural network models achieve higher prediction accuracy for predicted error within 5 % compared with regression models within 10 %, which suggests that the model is more reliable. Finally, the accuracy of models was demonstrated based on experimental verification, asserting that they can provide a foundation for developing a comprehensive prediction system to optimize the structural and processing of semi-solid magnesium alloys.</p>","PeriodicalId":18366,"journal":{"name":"Materialwissenschaft und Werkstofftechnik","volume":"56 4","pages":"565-574"},"PeriodicalIF":1.2,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Experimental analysis of physico-mechanical and wear characteristics of grewia optiva fibre/walnut shell particles reinforced epoxy hybrid composites","authors":"B. Pratap, V. K. Patel","doi":"10.1002/mawe.202400198","DOIUrl":"https://doi.org/10.1002/mawe.202400198","url":null,"abstract":"<p>In recent years, the investigation of natural fibres as viable replacements for engineered fibres has gained significant prominence. Natural fibres come with remarkable environmental attributes, including biodegradability and renewability. This work aims to analyze the physical, mechanical, and wear behavior of grewia optiva-walnut filler-based epoxy composites. The walnut shell content varies from 0 wt.–%–12 wt.–%, whereas grewia optiva fibre is kept constant (i. e., 10 wt.–%) for all fabricated compositions. The results revealed that the 9 wt.–% of walnut content-based composites exhibited a higher value of tensile strength (123.9 MPa) and flexural strength (52.03 MPa), whereas higher hardness, which is 38.33 HV 5, was achieved for the 12 wt.–% of walnut content. Moreover, the influence of selected control variables, i. e., walnut content, sliding velocity, normal load, and sliding distance, on the specific wear rate (SWR) of the composites was ranked using the Taguchi analysis. Further, scanning electron microscope (SEM) analysis has also been performed for fractured surfaces.</p>","PeriodicalId":18366,"journal":{"name":"Materialwissenschaft und Werkstofftechnik","volume":"56 4","pages":"612-624"},"PeriodicalIF":1.2,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. N. Andanje, J. W. Mwangi, B. R. Mose, S. Carrara
{"title":"Biofilaments from recycled high-density polyethylene and rice husks for fused filament fabrication","authors":"M. N. Andanje, J. W. Mwangi, B. R. Mose, S. Carrara","doi":"10.1002/mawe.202400168","DOIUrl":"https://doi.org/10.1002/mawe.202400168","url":null,"abstract":"<p>The benefits of green technology have industrial use of composites reinforced with biofibers garner attention. They are replacing conventional plastics due to their capability to solve environmental issues. Despite this shift in material development, the synthesis of biodegradable biocomposites still poses a challenge due to their wide range of properties. This work focuses on developing biofilaments for fused filament fabrication from recycled high-density polyethylene and rice husk waste in varying proportions to study the effect of their different ratios on the biofilaments. High-density polyethylene though very popular, has not been widely explored in fused filament fabrication due to warping challenges and high thermal shrinkage of printed parts upon solidification. The addition of organic fillers has been proposed as a way to reduce these challenges. Rice husk waste has been used as a filler in polyethylene for conventional processes such as extrusion, injection molding, and pressing but not widely in additive manufacturing. In this study, a particle size of less than 75 μm and the use of a compatibilizer improved its miscibility in the polymer's matrix. The highest composition of the biofilament achieved was 35 % rice husks, 35 % recycled high-density polyethylene, and 30 % compatibilizer, an improvement of the rice husk filler from previous studies. Printability was attained up to a biofilament composition of 40 % recycled high-density polyethylene, 30 % rice husks, and 30 % compatibilizer. The maximum tensile strength, tensile modulus, and maximum tensile strain of this biofilament were 8.53 MPa (standard deviation of 1.32 MPa), 6.6 % (standard deviation of 0.03 %), and 128.56 MPa (standard deviation of 13 MPa), respectively. Though the addition of rice husk filler reduced the tensile strength, there was an improvement in the crystallinity of the biofilament which improved the shrinkage and warpage of the printed part. This work thus demonstrated an improvement in the rice husk content as a filler in biofilaments made from recycled high-density polyethylene with enhanced biodegradability.</p>","PeriodicalId":18366,"journal":{"name":"Materialwissenschaft und Werkstofftechnik","volume":"56 4","pages":"581-600"},"PeriodicalIF":1.2,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B.O. Gerhards, B. Gerhards, B. Macke, P. Häuser, M. Schleser, P. Liebe
{"title":"Overlap joining of EN AW 7075 with laser beam welding in vacuum\u0000 Fügen von EN AW 7075 im Überlappstoß mit dem Laserstrahlschweißen im Vakuum","authors":"B.O. Gerhards, B. Gerhards, B. Macke, P. Häuser, M. Schleser, P. Liebe","doi":"10.1002/mawe.202400205","DOIUrl":"https://doi.org/10.1002/mawe.202400205","url":null,"abstract":"<p>The integration of EN AW 7075 aluminium in Body in White structures is a promising way to achieve weight savings, which in turn can make a significant contribution to reducing CO<sub>2</sub>-emissions. However, due to hot cracking susceptibility, conventional welding technologies offer limited possibilities to join the material. Therefore, laser beam welding in vacuum is introduced as a comparatively new joining technique. The investigations show, that it is possible to weld the EN AW 7075 alloy in an overlap joint configuration without pores or microcracks appearing in the weld seam. The weld seam has a very fine-grained structure, which presumably has a favourable effect on hot cracking mechanism. The prevention of cracking is likely due to the lower temperature gradient between the capillary wall and the fusion line caused by the low evaporation temperature due to the reduced pressure. The reduced temperature results in lower residual stresses, which presumably has a positive effect on the tendency to hot cracking. In addition, the fine-grained structures can absorb strain better than coarse grain structures, that usually occur in conventional laser beam welding.</p>","PeriodicalId":18366,"journal":{"name":"Materialwissenschaft und Werkstofftechnik","volume":"56 3","pages":"376-387"},"PeriodicalIF":1.2,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mawe.202400205","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}