title: Repeated crack healing in MAX-phase ceramics revealed by 4D in situ synchrotron X-ray tomographic microscopy.
abstract: MAX phase materials are emerging as attractive engineering materials in applications where the material is exposed to severe thermal and mechanical conditions in an oxidative environment. The Ti2AlC MAX phase possesses attractive thermomechanical properties even beyond a temperature of 1000 K. An attractive feature of this material is its capacity for the autonomous healing of cracks when operating at high temperatures. Coupling a specialized thermomechanical setup to a synchrotron X-ray tomographic microscopy endstation at the TOMCAT beamline, we captured the temporal evolution of local crack opening and healing during multiple cracking and autonomous repair cycles at a temperature of 1500 K. For the first time, the rate and position dependence of crack repair in pristine Ti2AlC material and in previously healed cracks has been quantified. Our results demonstrate that healed cracks can have sufficient mechanical integrity to make subsequent cracks form elsewhere upon reloading after healing.
authors.affiliation: Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands.
authors.forename: Willem G
authors.initials: WG
authors.lastname: Sloof
authors.affiliation: School of Materials, Manchester University M13 9PL, UK.
authors.forename: Ruizhi
authors.initials: R
authors.lastname: Pei
authors.affiliation: School of Materials, Manchester University M13 9PL, UK.
authors.forename: Samuel A
authors.initials: SA
authors.lastname: McDonald
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
authors.forename: Julie L
authors.initials: JL
authors.lastname: Fife
authors.affiliation: Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands.
authors.forename: Lu
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands.
authors.forename: Linda
authors.initials: L
authors.lastname: Boatemaa
authors.affiliation: Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands.
authors.forename: Ann-Sophie
authors.initials: AS
authors.lastname: Farle
authors.affiliation: School of Materials, Manchester University M13 9PL, UK.
authors.forename: Kun
authors.initials: K
authors.lastname: Yan
authors.affiliation: School of Materials, Manchester University M13 9PL, UK.
authors.forename: Xun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft, The Netherlands.
authors.forename: Sybrand
authors.initials: S
authors.lastname: van der Zwaag
authors.affiliation: School of Materials, Manchester University M13 9PL, UK.|Research Complex at Harwell, Didcot, Oxfordshire, OX11 0FA, UK.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Lee
authors.affiliation: School of Materials, Manchester University M13 9PL, UK.|Research Complex at Harwell, Didcot, Oxfordshire, OX11 0FA, UK.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Withers