Browsing by Author "Lavigne, O"

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Characterization of the residual stresses introduced by a new joining method in diamond and tungsten carbide composites
    (Curran Associates, Inc., 2019-05-29) Lavigne, O; Luzin, V; Mendez, M; Malik, AS; Rosas-Carrasco, O; Salvemini, F
    In this work, a co-sintering method was used to attach diamond to cemented carbide composites. The joining method consists of sintering a green part (ring) of cemented carbide (CC) around a thermally stable diamond composite (TSDC) part (plug) to radially contain it. During the sintering step, the green body shrinks to a controlled level and therefore forms interference fit between the two parts (mismatch between the inner diameter (ID) of the CC ring and the outer diameter (OD) of the TSDC cylinder). The residual stresses induced by this process as well as the bond strength between the CC and the TSDC parts were quantitatively evaluated. It is shown that the interface pressure between the two parts, and the level of residual stresses, increased with increase in the designed interference fit, as well as with the increase of the ID/OD ratios of the CC ring. For the chosen material combination (cemented carbide ring comprised 90 vol% WC and 10 vol% Co with medium coarse WC grains; diamond composite plug comprised 84 vol% diamond and 16 vol% SiC), the values of the hoop stresses at the interface in the CC ring measured by neutron diffraction was determined to be between 150 MPa and 550 MPa, depending on the ID/OD ratio. It was also found that for a given ID/OD ratio, the increase of the designed interference fit had little effect on that attained due to the plastic deformation of the cemented carbide material at the interface during the sintering (dynamic) process. A mechanical bond around 60 MPa was nevertheless achieved.
  • No Thumbnail Available
    Item
    The effect of the crystallographic texture on intergranular stress corrosion crack paths
    (Elsevier, 2014-11) Lavigne, O; Gamboa, E; Luzin, V; Law, M; Giuliani, M; Costin, W
    Intergranular stress corrosion cracking (IGSCC) crack paths usually travel perpendicular to the applied load direction. Some instances of crack paths propagating in directions away from the perpendicular have been observed in low carbon steels. This study shows that the crystallographic texture is a critical factor that drives the IGSCC crack path. Residual shear strain induced by shear texture (induced by rolling processes) explains the inclination of the cracks at a certain depth and the continuous propagation of the cracks along the transverse directions. The residual strains coming from the manufacturing processes determine the crack propagation paths. © 2014, Elsevier B.V.
  • No Thumbnail Available
    Item
    High-pH inclined stress corrosion cracking in Australian and Canadian gas pipeline X65 steels
    (Taylor & Francis, 2016-05-02) Lavigne, O; Gamboa, E; Griggs, J; Luzin, V; Law, M; Roccisano, A
    High-pH stress corrosion cracking is a form of environmental degradation of gas pipeline steels. The crack path is intergranular by nature and typically perpendicular to the maximum applied (hoop) stress (i.e. perpendicular to the pipe outer surface). Some unusual instances of cracks have been observed in Canadian and Australian X65 pipes, where cracks grow away from the perpendicular for considerable distances. This paper presents a comparative study in terms of crack morphology, mechanical properties and crystallographic texture for these Australian and Canadian pipe steels. It is shown that the crack morphologies are quite similar, the main difference being the angle at which the cracks propagate into the material. This difference could be explained by the different through-wall texture and grain aspect ratio measured in the two materials. The interdependency of crack tip plasticity, crack tip electrochemistry and anisotropy in microstructural texture seems to heavily affect the resulting inclined crack path. © 2016 Taylor & Francis
  • No Thumbnail Available
    Item
    In situ neutron diffraction measurement of strain relaxation in welds during heat treatment
    (Taylor & Francis Online, 2016-12-11) Alipooramirabad, H; Paradowska, AM; Lavigne, O; Ghomashchi, R; Reid, M
    Neutron diffraction (ND) is commonly used to investigate the stress redistribution before and after post-weld heat treatment (PWHT) in welded structures. However, there is a lack of information on the evaluations of strains during PWHT. The present work employed in situ ND to measure the relaxation of residual strains during conventional PWHT in multi-pass high-strength low-alloy steel welds. It was found that strain relaxation occurs principally during the heating stage of the heat treatment. The findings have important economic bearings and can be used to characterise comparable material combinations and optimise the PWHT process for high-strength low-alloy weld joints. This unique information also provides a valuable benchmark for the finite element modelling of this complex process. © 2021 Informa UK Limited
  • No Thumbnail Available
    Item
    Microstructural and mechanical factors influencing high pH stress corrosion cracking susceptibility of low carbon line pipe steel
    (Elsevier, 2014-10) Lavigne, O; Gamboa, E; Costin, W; Law, M; Luzin, V; Linton, V
    Several adjacent gas pipe sections were obtained from the field. These pipe sections had nominally identical manufacturing, construction, coating and operational conditions. Some sections were unaffected by stress corrosion cracking (SCC), whereas surrounding sections were affected by SCC. Slight differences in mechanical and microstructural properties were found between the two types of section. Residual stress/strain and hardness close to the outer surface of the pipes and high angle boundary fraction values were lower for the non-cracked pipe sections. Predominant 〈1 1 0〉//ND texture was also found at the outer surface of the non-cracked pipe sections. These characteristics lead to a lower crack growth rate in laboratory SCC experiments. These features being mainly a result of the line pipe steel manufacturing operations, appropriate metallurgical processes leading to low residual stress (6.2%YS), relatively low fraction of high angle boundaries (about 0.75) and predominant {1 1 0}〈1 1 0〉 texture in the material (or in the near surface) are expected to greatly improve the stress corrosion cracking resistance of line pipe steels on the field. © 2014, Elsevier Ltd.