A new method for quantifying anisotropic martensitic transformation strains accumulated during constrained cooling

A F Mark, R Moat, A Forsey, H Abdolvand, P J Withers

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Martensitic phase transformations during welding can play a major role in determining the final residual stresses and they can be anisotropic if the transformation occurs under stress. Traditionally, the Satoh test has been used to quantify the response, but it suffers from the fact that the temperature is not uniform along the specimen length, making it difficult to interpret the data. This shortcoming is overcome in our new experimental method using digital image correlation (DIC) to quantify the temperature dependent evolution of the transformation strain locally both parallel and perpendicular to an applied load, in this case for a high-strength low alloy (HSLA) steel and a tough, low transformation temperature weld consumable designed to mitigate tensile weld residual stresses. The method is able to separate the volumetric component of the transformation strain from the deviatoric transformation plasticity component. The volumetric component is shown to be independent of applied load, while the deviatoric component varies approximately linearly with applied load. For the HSLA steel studied here the method also reveals that the transformation start temperature rises under both tensile and compressive loading, confirming previous work. From a weld modelling viewpoint our method provides sufficient information to include the stress dependency of the anisotropic transformation strain in numerical finite element models of the weld process. © 2014 The Authors.
    Original languageEnglish
    Pages (from-to)354-361
    Number of pages8
    JournalMaterials Science and Engineering A
    Volume611
    Issue number0
    DOIs
    Publication statusPublished - 12 Aug 2014

    Keywords

    • Transformation induced plasticity
    • Dilatometry
    • Strain measurement
    • Finite element weld modelling

    Fingerprint

    Dive into the research topics of 'A new method for quantifying anisotropic martensitic transformation strains accumulated during constrained cooling'. Together they form a unique fingerprint.

    Cite this