Determination of interface toughness of functionally graded tungsten/EUROFER multilayer at 550 °C by analytical and experimental methods. (15th October 2018)

• Record Type: Journal Article
• Authors: Qu, D.; Gaganidze, E.; Vaßen, R.; Aktaa, J.
• Is Part Of: Engineering fracture mechanics. Volume 202(2018)
• Page Start: 487
• Page End: 499
• Publication Date: 2018-10-15
• Subjects: FG tungsten/EUROFER multilayer -- Interface toughness -- Bending test -- Energy release rate; FG(M) functionally graded (material) -- FW first wall -- DEMO demonstration fusion reactor -- RAFM reduced activation ferritic/martensitic -- VPS vacuum plasma spraying -- FE finite element -- CTOD crack-tip-opening displacement -- SEM scanning electron microscope -- EDX energy dispersive X-ray spectroscopy -- EDM electrical discharge machining; Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2018.09.016
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: We evaluated interface toughness of functionally graded multilayer. We performed three and four-point bending tests on pre-cracked specimens at 550 °C. The energy release rate was assessed analytically and experimentally. Relationship between microstructure and energy release rate of interfacial crack propagation was reported. Abstract: As armor coating, functionally graded (FG) tungsten/EUROFER multilayer was sprayed on EUROFER substrate for First Wall application in fusion field. Interface toughness between FG tungsten/EUROFER multilayer and EUROFER substrate was studied innovatively by a simple method based on the beam theory in this paper. To quantify interface toughness, the energy release rate was assessed by performing three and four-point bending tests on pre-cracked specimens at 550 °C and under high vacuum. The energy release rate during propagating of interfacial crack was determined to be 258 J/m 2 and 225 J/m 2 analytically and experimentally for samples with 3 and 5 layers as FG-layer, respectively, which were calculated based on multi bending tests. Cross-section and fracture microstructure show a vast of plasticity in FG-layer, particularly in FG-layer with a higher volume ratio of EUROFER. Interfacial fracture microstructure indicates interface adhesion consists of mechanical interlocking and metallurgical bonding.