{"title":"For THEY do not know what THEY are doing","authors":"R. Haubner","doi":"10.1515/pm-2023-0027","DOIUrl":"https://doi.org/10.1515/pm-2023-0027","url":null,"abstract":"Summary This article tries to work out how scientific data are generated and what causes lead to incorrect data. For this purpose, interactions between humans, computers and machines are analyzed. The handling of incorrect data that has already been published must also be clarified. The final, ethical question is: to what extent are people responsible for their actions if their decisions are shaped by incorrect data that are scientifically proven?","PeriodicalId":20360,"journal":{"name":"Practical Metallography","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90449607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Garment buttons from a Hallstatt period tumulus","authors":"R. Haubner","doi":"10.1515/pm-2022-1021","DOIUrl":"https://doi.org/10.1515/pm-2022-1021","url":null,"abstract":"Abstract A Hallstatt period burial mound (tumulus) in Schandorf, Burgenland, Austria, was opened and archaeologically investigated in 2021. Not only numerous pottery fragments, but also some garment buttons were found, one of which was provided for metallographic examinations, aiming at identifying the method of manufacture: soldering, riveting, casting? Prior to the metallographic examinations, micro-computed tomography (μm CT) was carried out at a resolution of 5 μm. The Figures show that large areas are oxidized. It was, however, found that metallic portions still existed. The overall appearance suggests investment casting as the manufacturing method. Analytical measurements revealed that the material is tin bronze. Despite severe corrosion, the metallographic sections still exhibit a clearly recognizable cast structure. There are presumably two types of corrosion: first, high temperature corrosion, which resulted in the formation of bronze oxides in the grain boundary areas during the cremation, and, second, corrosion in an aqueous environment, during which malachite formed. So far, no comparable studies can be found in the literature.","PeriodicalId":20360,"journal":{"name":"Practical Metallography","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82042233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Impact of tool rotational speed on the microstructural transitions and tensile properties of the dissimilar AZ80A-Mg – AA6061-Al joints fabricated by friction stir welding","authors":"P. Lokesh Kumar, P. Sevvel, T. Loganathan","doi":"10.1515/pm-2022-1029","DOIUrl":"https://doi.org/10.1515/pm-2022-1029","url":null,"abstract":"Abstract Distinct AZ80A-Mg alloy with AA6061-Al alloy plates were joined using friction stir welding and investigation regarding the weld features of the fabricated joints, related to microstructural attributes and mechanical properties was carried out by employing distinctive tool rotational speeds (1600, 1400, 1200, 1000 and 800 rpm). Tool possessing cylindrical pin with tapered profile was employed at constant traverse speed of 30 mm/min and was inserted towards AA6061 alloy plate at 0.5 mm offset distance. Experimental observations revealed that employment of tool rotational speed of 1200 rpm have generated ideal amounts of frictional heat, which have softened the ingredients of both the parent metals and have contributed for the transition of the grains into dynamically recrystallized, finely refined structures being distributed evenly in nugget zone. Moreover, this joint exhibited a tensile strength of 224 MPa (nearly 77.78 % of the tensile strength of AZ80A and 72.26 % of AA6061 alloy). Presence of river like patterns, rifts, tear crinkles at the middle portions of fractured surfaces, announced the brittle category of fracture of the flaw free joint and exhibited fracture at the horizon of the thermomechanically influenced zone and the nugget zone on retreatment side, where the warped structures have fused together.","PeriodicalId":20360,"journal":{"name":"Practical Metallography","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85821134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Picture of the Month","authors":"","doi":"10.1515/pm-2023-0021","DOIUrl":"https://doi.org/10.1515/pm-2023-0021","url":null,"abstract":"","PeriodicalId":20360,"journal":{"name":"Practical Metallography","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135997214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High Cycle Fatigue Failure of a Turbocharger Wheel","authors":"A. Neidel, B. Fischer, T. Gädicke","doi":"10.1515/pm-2023-0020","DOIUrl":"https://doi.org/10.1515/pm-2023-0020","url":null,"abstract":"Abstract A metallographic section from the crack area of an exhaust gas turbocharger was supplied by the customer. The shaft made of quenched and tempered low-alloy steel and the charger wheel made of a nickel-based superalloy were joined by laser welding. For design reasons, the root side of the weld contained a geometric notch, at which a high cycle fatigue crack initiated during the test facility operation of the turbocharger. At the time of examination, it went through almost the entire weld root. As a corrective action, it was recommended that the welded joint be replaced by a shrink fit.","PeriodicalId":20360,"journal":{"name":"Practical Metallography","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74011272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Sommer, Wolf-Achim Kahl, R. Fechte-Heinen, S. Hoja
{"title":"Microscopic Characterization of Compound Layers","authors":"M. Sommer, Wolf-Achim Kahl, R. Fechte-Heinen, S. Hoja","doi":"10.1515/pm-2022-1028","DOIUrl":"https://doi.org/10.1515/pm-2022-1028","url":null,"abstract":"Abstract The properties of the compound layer have a significant influence on the lifetime of nitrided surface layers. In addition to a sufficient thickness, the compound layer characteristics include the phase composition and the porosity. Complex methods such as GD-OES or XRD are already used to qualitatively and quantitatively determine the phase composition of the compound layer. Particularly with regard to the characterization of the pore seam, no method has yet been identified that can be clearly recommended. In this work, the extent to which compound layers can already be characterized with the aid of microscopic examination methods is shown. For this purpose compound layers with varying thickness, phase composition and porosity were formed in the surface area of the material EN31CrMoV9 and EN42CrMo4 by different nitriding processes. It is demonstrated how the phase composition of compound layers can be studied qualitatively by means of special etchants on metallographic cross sections and subsequently quantitatively by image analysis. A more extensive characterization of the pore seam beyond the state of the art could be performed by scanning electron microscopy studies as well as 3D X-ray microscopy.","PeriodicalId":20360,"journal":{"name":"Practical Metallography","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77613838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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