Mechanical characterization of thermal activated low-carbon recycled cement mortars

2019 ◽  
Vol 218 ◽  
pp. 377-389 ◽  
Author(s):  
J.A. Bogas ◽  
A. Carriço ◽  
M.F.C. Pereira
2020 ◽  
Vol 988 ◽  
pp. 206-211
Author(s):  
Alfirano ◽  
Purwaningtyas Agustini ◽  
Sumirat Iwan

Co-Cr-Mo alloys is the material used as a biomedical implant in human body. This material is widely used because they have excellent in corrosion and wear resistance. In this study, microstructure and results of tensile test that were affected by carbon and nitrogen were investigated. The specimens of Co-Cr-Mo alloy were made by investment casting. The compositions of the alloys are Co-28Cr-6Mo-0.8(Si, Mn, Fe)-0,2Ni-(0.08-0.25)C-(0-0.2)N. After that process, microstructure of the alloys is characterized by, SEM/EDX and XRD testing using bulk and electrolytic extracted specimens. The mechanical properties were determined by tensile test. The precipitate content in as-cast alloys was higher when carbon and nitrogen was added. The main precipitate formed in the specimens with variations in carbon and nitrogen is M23X6 type, π-phase, χ-phase, and σ-phase. Carbon and nitrogen promoted M23X6 type and π-phase precipitation, respectively, meanwhile χ-phase was formed in the alloys with low carbon content. The addition of carbon and nitrogen shows an increased in yield strength, tensile strength and elongation of as-cast Co-28Cr-6Mo-0.8(Si, Mn, Fe)-0,2Ni-(0.08-0.25)C-(0-0.2)N alloys.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 810
Author(s):  
Elena Scutelnicu ◽  
Mihaela Iordachescu ◽  
Carmen Catalina Rusu ◽  
Danut Mihailescu ◽  
José Luis Ocaña

This paper addresses the metallurgical and mechanical characterization of dissimilar joints made by laser autogenous welding between thin sheets of low-carbon steel (CS) and austenitic stainless steel (SS). The welding technology applied, previously optimized to produce sound dissimilar joints, is based on the heat source displacement from the weld gap centerline towards CS, in order to reduce the SS overheating. The research includes optical microscopy observations, energy dispersive X-ray analysis (EDX) to assess the wt% of Cr, Ni, and Fe in all regions of the dissimilar welded joint, hardness measurements, and tensile tests of transverse-welded flat specimens. In comparison with classical determination of the joint overall mechanical characteristics, the novelty of this research consists of experimental assessment of the local mechanical behavior of the fusion and heat affected zones by using a digital image correlation technique (VIC-2D). This is an efficient tool for determining the constitutive properties of the joint, useful for modelling the mechanical behavior of materials and for verifying the engineering predictions. The results show that the positive difference in yielding between the weld metal and the base materials protects the joint from being plastically deformed. As a consequence, the tensile loading of flat transverse specimens generates the strain localization and failure in CS, far away from the weld.


Author(s):  
L. S. Lin ◽  
K. P. Gumz ◽  
A. V. Karg ◽  
C. C. Law

Carbon and temperature effects on carbide formation in the carburized zone of M50NiL are of great importance because they can be used to control surface properties of bearings. A series of homogeneous alloys (with M50NiL as base composition) containing various levels of carbon in the range of 0.15% to 1.5% (in wt.%) and heat treated at temperatures between 650°C to 1100°C were selected for characterizations. Eleven samples were chosen for carbide characterization and chemical analysis and their identifications are listed in Table 1.Five different carbides consisting of M6C, M2C, M7C3 and M23C6 were found in all eleven samples examined as shown in Table 1. M6C carbides (with least carbon) were found to be the major carbide in low carbon alloys (<0.3% C) and their amounts decreased as the carbon content increased. In sample C (0.3% C), most particles (95%) encountered were M6C carbide with a particle sizes range between 0.05 to 0.25 um. The M6C carbide are enriched in both Mo and Fe and have a fee structure with lattice parameter a=1.105 nm (Figure 1).


2018 ◽  
Author(s):  
Devon Jakob ◽  
Le Wang ◽  
Haomin Wang ◽  
Xiaoji Xu

<p>In situ measurements of the chemical compositions and mechanical properties of kerogen help understand the formation, transformation, and utilization of organic matter in the oil shale at the nanoscale. However, the optical diffraction limit prevents attainment of nanoscale resolution using conventional spectroscopy and microscopy. Here, we utilize peak force infrared (PFIR) microscopy for multimodal characterization of kerogen in oil shale. The PFIR provides correlative infrared imaging, mechanical mapping, and broadband infrared spectroscopy capability with 6 nm spatial resolution. We observed nanoscale heterogeneity in the chemical composition, aromaticity, and maturity of the kerogens from oil shales from Eagle Ford shale play in Texas. The kerogen aromaticity positively correlates with the local mechanical moduli of the surrounding inorganic matrix, manifesting the Le Chatelier’s principle. In situ spectro-mechanical characterization of oil shale will yield valuable insight for geochemical and geomechanical modeling on the origin and transformation of kerogen in the oil shale.</p>


2017 ◽  
Vol 5 (3) ◽  
pp. 8
Author(s):  
KUMAR DINESH ◽  
KAUR ARSHDEEP ◽  
AGGARWAL YUGAM KUMAR ◽  
UNIYAL PIYUSH ◽  
KUMAR NAVIN ◽  
...  

Author(s):  
Alexandre Luiz Pereira ◽  
Rafael Oliveira Santos ◽  
DOINA BANEA ◽  
Álisson Lemos

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