{"title":"Characterization and Testing of High-Entropy Alloys from AlCrFeCoNi System for Military Applications","authors":"V. Geantǎ, I. Voiculescu","doi":"10.5772/intechopen.88622","DOIUrl":"https://doi.org/10.5772/intechopen.88622","url":null,"abstract":"High-entropy alloys (HEAs) can be obtained using various metallurgical processes such as vacuum arc remelting (VAR), induction melting, powder metallurgy, additive manufacturing, plasma sintering of powders, etc. Among these methods, the obtaining process in the VAR plant provides superior homogeneity characteristics for metal matrices, simultaneously with advanced purity, due to the high level of protection of the melts. The chapter presents a series of results on alloys with high entropy from the AlCrFeCoNi system, which can be used for various applications, including in the military field, for the realization of high-speed penetration protection panels. Experimental alloys were obtained by melting in electric arc under an argon atmosphere, using high-purity raw materials (greater than 99.5 wt%), and homogenization is ensured by successive five-times remelting of mini-ingots. The obtained alloys were subjected to microstructural analyses, mechanical tests, and also dynamic impact tests using incendiary perforation projectiles. At the same time, some tests were carried out on ballistic packages made of different materials, including high-entropy alloys. The results obtained in mechanical tests revealed high values of microhardness (over 600 HV 0.1 ) as well as compressive strengths above 2000 MPa. The mechanical characteristics of these alloys can undergo substantial changes by applying several heat treatments.","PeriodicalId":342991,"journal":{"name":"Engineering Steels and High Entropy-Alloys","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115215849","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 Entropy Alloys for Medical Applications","authors":"V. Geantǎ, I. Voiculescu, P. Vizureanu, A. Sandu","doi":"10.5772/intechopen.89318","DOIUrl":"https://doi.org/10.5772/intechopen.89318","url":null,"abstract":"A wide variety of metallic biomaterials have been developed so far, including various types of alloys. However, there is a strong need in the medical field for new solutions in what concerns metallic biomaterials with superior biocompatibility and mechanical properties in order to meet future requirements, including the recently developed high entropy alloys (HEAs). This chapter presents some characteristics of high entropy biocompatible metallic alloys produced in an electric-arc remelting furnace in argon inert atmosphere. The effects of the chemical elements used, the microstructural features, and some mechanical characteristics, both in the cast state or after some heat treatments, are highlighted.","PeriodicalId":342991,"journal":{"name":"Engineering Steels and High Entropy-Alloys","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123472488","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":"Light-Weight and Flexible High-Entropy Alloys","authors":"Yasong Li, Yong Zhang","doi":"10.5772/INTECHOPEN.88332","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.88332","url":null,"abstract":"The lightweight and flexible materials can improve people’s quality of daily life; in addition, the materials can be widely used in aerospace, automotive, consumer elec-tronics, etc. Recently, high-entropy alloys had become hot issues in materials science with many excellent properties; therefore, we can combine the design ideas of high-entropy alloys with lightweight materials and flexible materials, taking into account the advantages of two types of materials, and promoting the development and progress of new materials. In the chapter, we will elaborate on the relationship between the microstructure and properties of lightweight high-entropy alloys and the design ideas of high-entropy alloys with flexible materials that were investigated in recent years. Furthermore, as the microstructure and mechanical properties of the alloys exhibit the nonlinear behaviors with entropy on high-entropy alloys, we would like to define the lightweight high-entropy alloy as the density is lower than 6 g/cm 3 , the mix-entropy of these alloys is higher than 1R (here, R is gas constant), and the number of components is four or more. Finally, it is expected to broaden the research field of high-entropy alloys and provide some new directions for the development of new materials.","PeriodicalId":342991,"journal":{"name":"Engineering Steels and High Entropy-Alloys","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114191542","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}
L. Reclaru, L. Ardelean, A. Grecu, Cătălin Adrian Miu
{"title":"Multicomponent Alloys for Biomedical Applications","authors":"L. Reclaru, L. Ardelean, A. Grecu, Cătălin Adrian Miu","doi":"10.5772/INTECHOPEN.88250","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.88250","url":null,"abstract":"Titanium alloys are considered to be the most advanced materials for orthopedic implants due to the favorable combination of mechanical properties, low density, tissue tolerance, high strength-to-weight ratio, good resistance to corrosion by body fluids, biocompatibility, low density, nonmagnetic properties, and the ability to join with the bone. This is the reason why we decided to assess the resistance of two titanium alloys currently used for orthopedic implants, namely, Ti6Al7Nb and Ti6Al4V, as reference, to cyclic fatigue by dynamic tests with crevice corrosion stimulation. According to the results obtained, the examined electrochemical quantities, the visual and SEM observations, and EDX analysis reveal better corrosion behavior of the prostheses made of Ti6Al4V—anodized series compared to prostheses made of Ti6Al7Nb. The further comparison of two explanted proximal modules, made of Ti6Al7Nb and Ti6Al4V, to the same type of prostheses evaluated by cyclic fatigue dynamic tests with crevice corrosion stimulation reveals that there are significant similarities, in particular with regard to the electrolyte diffusion, deposition of products and corrosion. Cation extraction tests which were carried out for Ti6Al7Nb prostheses that have undergone particular surface treatments show significant differences depending on the surface treatment and demonstrate that orthopedic implant materials are not “inert.”","PeriodicalId":342991,"journal":{"name":"Engineering Steels and High Entropy-Alloys","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130853990","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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