Microstructure, mechanical properties, and brittle fracture of a cast nickel-aluminum-bronze (NAB) UNS C95800. (October 2021)

• Record Type: Journal Article
• Authors: Tavares, S.S.M.; Mota, N.M.; da Igreja, H.R.; Barbosa, C.; Pardal, J.M.
• Is Part Of: Engineering failure analysis. Volume 128(2021)
• Publication Date: 2021-10
• Subjects: Nickel-aluminum-bronze -- Brittle fracture -- Fractography; NAB Nickel Aluminum Bronze -- MAB Manganese Aluminum Bronze -- PWHT Post weld heat treatment -- SEM Scanning electron microscope -- LOM Light optical microscope -- EDS Energy dispersive spectroscopy -- HBN Brinell hardness -- XRD X-ray diffraction -- WAMM wire-arc additive manufacturing -- FCC Face centered cubic -- BCC Body centered cubic -- σ true stress -- ε true strain -- n work hardening exponent -- K constant in Hollomon's and Ludwik's equations -- R2 correlation coefficient -- β, β′, kI, kII, kIII and kIV phases of NAB alloys; System failures (Engineering) -- Periodicals; Fracture mechanics -- Periodicals; Reliability (Engineering) -- Periodicals; Pannes -- Périodiques; Rupture, Mécanique de la -- Périodiques; Fiabilité -- Périodiques; Fracture mechanics; Reliability (Engineering); System failures (Engineering); Periodicals; Electronic journals; 620.112
• DOI: 10.1016/j.engfailanal.2021.105606
• Languages: English
• ISSNs: 1350-6307

Abstract

Highlights: Cast nickel-alluminum-bronze (NAB) treated at 675 °C presents brittle fracture in tensile and Charpy impact tests. Fracture surfaces are characterized by sub-microdimples and small cracks. Tensile curves can be modeled by Hollomon's and Ludwik's models. Abstract: Nickel aluminum bronzes (NAB) are corrosion resistant alloys used in seawater environments as parts of valves, fittings, ship propellers, pumps, pump shafts, and heat exchangers. As many other alloys, NAB can be cast or wrought. More recently, additive manufacture methods have been studied for this class of materials. Corrosion problems are reported in the literature, and are related to the presence of β phase, de-alloying and low aluminum content. In this work, the mechanical behaviour of a cast NAB alloy was investigated by tensile and impact tests. The material has been heat treated to eliminate the deleterious β′ phase. Brittle fractures were observed in the tensile and Charpy impact tests, and the micro-mechanisms of these fractures were investigated by fractography in the scanning electron microscope (SEM). The true stress–strain curve of the tensile test was successfully modelled by Hollomon's and Ludwik's equations. The results are useful to the application of cast NAB UNS C95800 alloy.