Kathy González Jiménez, Joaquín E. González Hernández, J. M. Cubero-Sesin, Jeremy Barrantes Rodríguez, Z. Horita
{"title":"Superplasticity of Ti-6Al-7Nb alloys with different initial microstructures processed by high-pressure torsion","authors":"Kathy González Jiménez, Joaquín E. González Hernández, J. M. Cubero-Sesin, Jeremy Barrantes Rodríguez, Z. Horita","doi":"10.21741/9781644902615-7","DOIUrl":"https://doi.org/10.21741/9781644902615-7","url":null,"abstract":"Abstract. Ti-6Al-7Nb alloy was quenched below and above the β-phase field and processed by high-pressure torsion (HPT) to produce different grain sizes in the ultra-fine range. The influence of temperature and strain rate over the superplastic properties, activation energy and strain rate sensitivity were evaluated by high temperature tensile tests. The mechanical properties were complemented with Vickers microhardness measurement of heat treated and HPT-processed samples. The crystallographic analysis was performed through XRD and EBSD studies in the grip and tip of the high temperature tensile specimens. Microhardness measurements show significant hardening with respect to the imposed strain after HPT. Meanwhile, high superplastic elongation of 1200% was accomplished at 850 °C with a strain rate of 2x10-3 s-1. EBSD studies of the failed specimens suggest that the tip part exhibited dynamic recrystallization during tensile test, which produced a larger grain size of ~5.1 µm and higher fraction of β phase of 3.7%, with respect to the grip part under static recrystallization, which attained ~3.4 µm grain size and 3.3% β phase fraction.","PeriodicalId":242571,"journal":{"name":"Superplasticity in Advanced Materials","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128191235","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}
C. Gennari, L. Pezzato, Núria Llorca i Isern, I. Lopez, José M. Cabrera Marrero, M. Chand, Antoni Roca, I. Calliari
{"title":"Effect of severe plastic deformation on microstructure and properties of duplex stainless steel","authors":"C. Gennari, L. Pezzato, Núria Llorca i Isern, I. Lopez, José M. Cabrera Marrero, M. Chand, Antoni Roca, I. Calliari","doi":"10.21741/9781644902615-23","DOIUrl":"https://doi.org/10.21741/9781644902615-23","url":null,"abstract":"Abstract. The excellent performance of duplex and super duplex stainless steels due to their high corrosion resistance and high mechanical strength is directly related to their austeno-ferritic microstructure. However, these steels may suffer the formation of secondary brittle phases when they reach temperatures between 600°C and 950°C causing catastrophic service failure of components. In order to understand the influence of the mechanical history of the steel, the equal channel angular pressing was applied on UNS S32750 bar samples. ECAP is processed by using a hydraulic press (DE-80). Microstructural characterization was carried out on the severe plastic deformed samples by means of OM, SEM and EBSD. Ultimate tensile strength has improved with a low decreasing of elongation after the first pass. The ECAP process resulted to produce a faster precipitation of secondary phases if compared with the non-ECAP samples.","PeriodicalId":242571,"journal":{"name":"Superplasticity in Advanced Materials","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127799149","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}