Investigation of the Microstructure and Corrosion Properties of Friction Stir Processed Cast NiAl Bronze

Lv, Ying; Wang, Liqiang; Xu, Xiaoyan; Han, Yuanfei; Lü, Weijie

doi:10.2320/matertrans.m2015125

Cited by 14 publications

(9 citation statements)

References 36 publications

(38 reference statements)

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“…Microstructural characteristics of friction stir processed and post heat treated NAB samples were examined with a JEM-2100F scanning electron microscope (SEM) equipped with electron backscatter diffraction (EBSD) and a JEM-200 EX transmission electron microscope (TEM). The sample preparation methods for SEM, EBSD, TEM were described in detail in aforementioned studies [18,19,28]. It was noted that stir zones of friction stir processed NAB alloys present inhomogeneous microstructures due to different deformation degrees and peak temperatures in various subregions of friction stir processed samples [13].…”

Section: Methodsmentioning

confidence: 99%

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Strengthening mechanism of friction stir processed and post heat treated NiAl bronze alloy: Effect of rotation rates

Ding

Han

et al. 2017

Materials Science and Engineering: A

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In this work, NiAl bronze (NAB) alloys were subjected to friction stir processing (FSP) at a constant traverse speed of 100 mm/min and rotation rates of 600 rpm, 800 rpm, 1000 rpm and 1200 rpm, respectively. Thereafter, heat treatment was performed at 675 °C for 2 h. The effects of rotation rates on strengthening mechanisms of friction stir processed and post heat treated NAB alloy were studied. The results showed that friction stir processed NAB alloy microhardness was increased as the rotation rate increased. During friction stir processing, martensite nanotwins could be formed due to high strain rates and peculiar martensitic structures of NAB alloys. A rotation rate increase, increased peak temperatures and strain rates in friction stir processed NAB alloys, leading to a significant amount of martensite nanotwins formation. As rotation rates increased from 600 rpm to 1200 rpm, in addition to grain refinement effects, the strengthening mechanism of friction stir processed NAB alloys gradually changed from secondary phase strengthening to solid solution, dislocations and nanotwin strengthening. During post heat treatment, discontinuous static recrystallization occurred and β′ phase decomposed into α and κ phases. Highest microhardness values were obtained at the rotation rate of 800 rpm and the uniformly distributed second phases formed during friction stir processing contributed mainly to higher microhardness

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Section: Methodsmentioning

confidence: 99%

“…2(b)), finer α and β' phases were observed and finer κ phases are uniformly distributed in the matrix and in β' phases. It is noted that the FSP800 processed on the forged NAB alloy displays different microstructures compared to that processed on as cast alloy [28].…”

Section: Structural Characteristicsmentioning

confidence: 97%

Strengthening mechanism of friction stir processed and post heat treated NiAl bronze alloy: Effect of rotation rates

Ding

Han

et al. 2017

Materials Science and Engineering: A

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“…These precipitates are distinguished by their morphologies and chemical composition, as detailed in Table 1, taken from [45]. Fine k 4 precipitates appear inside the grains [46]. Lamellar Ni rich precipitates at the grain boundaries are identified as k 3 , which can also be of globular form because of the heat treatment [45].…”

Section: Microstructurementioning

confidence: 99%

A probabilistic approach for high cycle fatigue of Wire and Arc Additive Manufactured parts taking into account process-induced pores

Bercelli

Moyne

D’Hondt

et al. 2021

Additive Manufacturing

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Wire and Arc Additive Manufacturing (WAAM) is a direct-energy deposition technique (unlike SLM or EBM) that builds up a part in a layer-by-layer fashion, each layer being constituted of interlaced weld beads. It is the best suited Additive Manufacturing (AM) technique for large structures thanks to its high deposition rate (5kg/h). The resulting material shows a rough surface, strong residual stress induced by its complex thermal history, a heterogeneous microstructure marked by the different weld passes as well as defects formed by gas pockets. Despite their rarity, pores are found to have a first-order influence on the fatigue life of machined specimens. The discrepancy in their size (> 100µm) and position is responsible for a considerable scatter that makes classical fatigue tests ineffective. The aim of this study is to propose a novel approach to take into account the effect of rare WAAM-induced defects in high cycle fatigue. To achieve this, numerical porous structures are generated from the knowledge of the real pore population determined by tomography. Their fatigue performances are predicted via a two-scale probabilistic model identified on experimental self-heating results, on which pores have no influence. In that sense, the probabilistic model describes the behaviour of a virtually healthy material. Then, by computing a database of representative pore cases, the whole bundle of Wöhler curves for each numerical porous structure is determined. Finally, the numerical fatigue scatter is in close agreement with experimental data, and it is shown that the ranking in pore criticality according to the model matches the fractography observations. Keywords: Wire and Arc Additive Manufacturing (WAAM) ; High cycle fatigue ; Pores ; Self-heating ; Poisson point process Draft articleIRDL fatigue life of the position of an isolated pore over its size. From this observation a novel approach is proposed in [16], where the total plastic zone in the vicinity of a defect is considered from Finite Element Analysis (FEA). Although gas pores found in WAAM parts have much larger dimensions (>100µm) and have smooth near-spherical shapes [23][24][25], to which notch fatigue and crack initiation approaches are best suited [26,27].In the case of WAAM, a low density of defects can be achieved using the Cold Metal Transfer (CMT) technology [28,29]. Typical WAAM defects are round smooth pores, with sizes ranging from a few micrometers to more than half a millimeter [23,30]. Fatigue samples extracted from optmized WAAM blocks show rare isolated pores with an important discrepancy in size and distance to free surface. As a result, a considerable scatter in fatigue data is observed [31] (for example compared to casting materials), posing quite a challenge to the assessment of fatigue properties by conventional methods (ASTM E466-15 standard [32], the staircase method [33]). These samples do not constitute a Representative Volume Element (RVE) of the material's fatigue behaviour: each sample can be seen as a unique structure. This is t...

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“…NAB alloy has been widely used for marine engineering equipment, by virtue of its good combination of mechanical properties and corrosion resistance [8,9,10]. Considerable research has been devoted to studying the corrosion behavior of NAB alloy to try and reveal the mechanism of corrosion attack.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the Corrosion Product Film on Nickel-Aluminum Bronze and Its Corrosion Behavior in 3.5 wt % NaCl Solution

et al. 2019

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The in-situ studies of the corrosion product film on nickel-aluminum bronze are significant for explaining the mechanism of its corrosion resistance. In this paper, the corrosion behavior of nickel-aluminum bronze and the formation process of the protective film in 3.5 wt % NaCl solution are systematically investigated. The results of scanning electron microscope analysis and electrochemical tests indicate that the corrosion resistance of nickel-aluminum bronze is improved due to the formation of the corrosion product film. The change of local electrochemical property on the corrosion product film during the immersion time is evaluated via in-situ scanning vibrating electrode technique, and it reveals the evolution rules of ionic flux in real time. The formation process of the protective film on different phases in nickel-aluminum bronze is observed directly by in-situ atomic force microscopy as height change measurements. The α phases at different locations present different corrosion behaviors, and the lamellar α phase within the α + κIII eutectoid structure gets more serious corrosion attack. The κ phases establish a stable and dense protective film in short time, preventing the corrosion attack effectively. The β′ phase, however, suffers the most serious corrosion damage until a protective film is formed after 150 min of immersion.

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Investigation of the Microstructure and Corrosion Properties of Friction Stir Processed Cast NiAl Bronze

Cited by 14 publications

References 36 publications

Strengthening mechanism of friction stir processed and post heat treated NiAl bronze alloy: Effect of rotation rates

Strengthening mechanism of friction stir processed and post heat treated NiAl bronze alloy: Effect of rotation rates

A probabilistic approach for high cycle fatigue of Wire and Arc Additive Manufactured parts taking into account process-induced pores

Evolution of the Corrosion Product Film on Nickel-Aluminum Bronze and Its Corrosion Behavior in 3.5 wt % NaCl Solution

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