{"title":"Characterization and comparison of cobalt-base and nickel-base alloys with iron-base intermetallic hard alloys used in wear protection","authors":"S. Friederichs, S. Lorenz","doi":"10.1515/pm-2024-0012","DOIUrl":"https://doi.org/10.1515/pm-2024-0012","url":null,"abstract":"\u0000 In wear protection, cobalt-base or nickel-base materials are very often used for coatings in order to increase the functionality and service life of components. These materials such as stellite, the nickel-base alloy Colmonoy 56 or Tribaloy T400 are characterized by a high resistance to abrasion, adhesion as well as excellent corrosion resistance even at higher temperatures.\u0000 Given the criticality of cobalt and partly also nickel, it is necessary to look for more sustainable alternatives to be used in wear protection. One possibility is to further develop iron-base materials so that they can be used in wear protection to prevent both abrasion and adhesion. In this context, sufficient corrosion resistance is desirable. This paper will elaborate on the development of a novel intermetallic iron-base hard alloy.","PeriodicalId":508095,"journal":{"name":"Practical Metallography","volume":"150 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140446545","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":"Discoloration on Laser Welds of AISI 321 Tubes","authors":"A. Neidel, J. Rockel, S. Riesenbeck","doi":"10.1515/pm-2024-0015","DOIUrl":"https://doi.org/10.1515/pm-2024-0015","url":null,"abstract":"\u0000 In this contribution, a fabrication problem is discussed, related to Laser Beam Welding (LBW). Strictly speaking, the case study presented herein does not constitute a failure as such, since the subject components never made it to component service. In the narrow sense of the word, a component failure happens if and when a part does no longer serve its proper function. This is definitely not the case in the study put forward in this paper. However, one could argue that a product that cannot be marketed for lack of certain properties, or because of certain shortcomings, is rendered worthless for the manufacturer and this, in turn, could be considered a failure. In this case study, the issue of discoloration on the surfaces of welded austenitic stainless steel is discussed. This is a well-known and well-researched fabrication problem. Dependent upon service conditions of affected parts, discoloration might be detrimental to the normally outstanding corrosion resistance of this class of high-alloy steels.","PeriodicalId":508095,"journal":{"name":"Practical Metallography","volume":"194 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140448423","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":"Microstructural analysis of the cast and melt-spun high entropy noble alloy Ag20Pd20Pt20Cu20Ni20","authors":"L. Simić, A. Kneissl, I. Anžel","doi":"10.1515/pm-2024-0014","DOIUrl":"https://doi.org/10.1515/pm-2024-0014","url":null,"abstract":"\u0000 High entropy alloys (HEA) represent a relatively new class of materials with promising properties for various applications. In recent years, these alloys have received considerable attention as potential heterogeneous catalysts in chemical and electrochemical reactions. Their enhanced catalytic activity is controlled by chemical composition, surface atomic coordination, electronic configuration and degree of microstructural metastability. Single-phase HEAs are of particular importance, because they possess a uniform microstructure that is useful for designing and prediction of mechanical and potential functional properties. The cooling rate has a significant impact on the formation of the microstructure, affecting the size of grains, as well as distribution and composition of precipitates and phases that are being formed during solidification. The influence of different cooling rates on the microstructure of the alloy Ag20Pd20Pt20Cu20Ni20 was studied in our research work. The microstructure and phase constituents were characterised by Scanning Electron Microscopy and X-ray Diffraction. Liquid phase separation with a consequential monotectic reaction resulted in an anomalous multiphase cast microstructure. With an increase in the cooling rate using the melt spinning technique, the number of formed phases and the size of the grains decreased and the high entropy supersaturated solid solution was attained, as the atoms in the alloy did not have enough time to diffuse and to rearrange themselves into a stable, ordered structure. It was also confirmed that higher cooling rates cause severe lattice distortion and create coordinatively unsaturated sites at the surface which are essential for the bonding and activation of the reactants and therefore improve the potential catalytic properties of the Ag20Pd20Pt20Cu20Ni20 alloy significantly.","PeriodicalId":508095,"journal":{"name":"Practical Metallography","volume":"69 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140448661","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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