Tensile deformation behaviour of ferritic-pearlitic steel studied by digital image correlation method

Abstract

Tensile deformation behaviour of ferritic-pearlitic steel was studied by the digital image correlation (DIC) method. Room temperature tensile tests were carried out at an initial strain rate of 1 × 10 −3 s −1 up to a defined elongation or fracture. The elongation and contraction were measured on the surface of cylindrical tensile specimens with random speckle pattern using stereo CCD camera system. The DIC elongation data were related to the data measured by an extensometer touching the specimens. The data from the DIC method were used for calculations of true stress-true strain tensile curves, strain hardening exponents and work hardening rates during uniform deformation up to the onset of plastic instability as well as non-uniform deformation during necking. Numerical simulations of strain fields within the gauge region of the specimens using finite element method were validated by the experimental data from the DIC method.

Effect of hydrogenation on deformation behaviour of ferritic-pearlitic steel studied by digital image correlation method

“…Figure 6 shows the typical pictures of the tensile specimen taken by the CCD cameras. The random black colour speckles pattern is very well visible on the gauge surface before and after tensile testing [7,8]. The green line along the gauge section of the spec-imen is drawn by the video extensometer of Mercury RT software before ( Fig.…”

“…In order to understand tensile deformation behaviour related to intrinsic and extrinsic properties of materials, not only experiments using precise machines and sensors but also the deep interpretation of the deformation curves, specimen geometries, and specific testing con-ditions are important. Contactless sensing digital image correlation (DIC) optical method for tracking and image registration technique allows accurate 2D and 3D measurements of a gauge section of specimens during tensile testing and can provide new information about tensile deformation behaviour of materials [6][7][8][9][10]. The additional data obtained during testing can be used to understand more deeply whole tensile deformation process including calculations of local elongation, local contraction and redistribution of strain fields on the surface of the specimen.…”

Effect of carbon on the room temperature compressive behaviour of Ti-44.5Al-8Nb-0.8Mo-xC alloys prepared by vacuum induction melting

“…2b) can be fitted by a log-normal distribution function. Table 2 summarises mean length of the major axis, mean length of the minor axis, average shape factor defined elsewhere [26] and volume fraction of the regular, plate-like and irregular shaped primary carbide particles in the specimens before compression testing. The increase in the carbon content from 1.4 to 3.6 at.% leads to an increase in the volume fraction of the primary carbide particles from 6.0 to 14.9 vol.%.…”

Influence of austempering temperature and salt bath agitation on microstructure and mechanical properties of austempered ductile iron

“…Isothermal heat treatments of ductile cast iron lead *Corresponding author: e-mail address: Niksa.Catipovic@fesb.hr to the formation of completely new phase in austempered ductile iron (ADI) known as ausferrite. The ADI has a unique microstructure and significantly better mechanical properties (hardness, toughness, and strength) than those of as-cast ductile iron [2][3][4]. The microstructure of ADI is a mixture of fine acicular ferrite and stable, high carbon enriched retained austenite called ausferrite [3,4].…”

“…The ADI has a unique microstructure and significantly better mechanical properties (hardness, toughness, and strength) than those of as-cast ductile iron [2][3][4]. The microstructure of ADI is a mixture of fine acicular ferrite and stable, high carbon enriched retained austenite called ausferrite [3,4]. Compared with pearlitic, ferritic or martensitic microstructures, the tensile strength of the ausferrite is nearly doubled at a given ductility level [4][5][6][7][8][9][10].…”