Corrosion properties of friction–stir processed cast NiAl bronze

Ni, D.R.; Xiao, B.L.; Y., Z.; Qiao, Yanxin; Zheng, Yuan

doi:10.1016/j.corsci.2010.02.026

Cited by 125 publications

(51 citation statements)

References 51 publications

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“…The results obtained in this study agree with the findings of Ni et al [25] who conducted a similar experiment which found that the weight loss of cast NAB after 50 hour was close to 9 grams/m 2 , but the weight loss of FSP NAB was just above 5 grams/m 2 . Ni et al stated that the FSP sample showed a much lower corrosion rate than the cast sample due to the optimisation of the microstructure, such as the refinement of grain size, elimination of porosities, and alleviation of the K phase segregation.…”

Section: Corrosion Testingsupporting

confidence: 83%

“…The estimated average grain size of this processed top layer is 1 to 5 lm, a very significant reduction in comparison to an average grain size of 100 to 150 lm for the cast material shown in Figure 6(a). These results are similar to those reported by others [25] who have applied FSP to NAB using conventional machines rather than robotic manipulators.…”

Section: B Microstructural Analysissupporting

confidence: 82%

“…From these figures, it can be seen that the FSP NAB succeed to refine the grain structure and eliminates porosity defect and homogenised the microstructure, and therefore increase the hardness, tensile properties, and fatigue strength. [25] The effects of FSP and high cooling rates at the processed surface create highly packed grain structures that alter the mechanical properties. Wang et al [26] state that higher grain boundary densities lead to the formations of a stable and proactive passive film.…”

Section: B Microstructural Analysismentioning

confidence: 99%

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Feasibility Study of Low Force Robotic Friction Stir Process and its Effect On Cavitation Erosion and Electrochemical Corrosion for Ni Al Bronze Alloys

Ahmad

Pan

et al. 2014

Metall Mater Trans B

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Robotic friction stir processing (FSP) has not been widely researched to date. This is perhaps due to the limited force capabilities of industrial robots in comparison with dedicated commercial FSP equipment. When operating a FSP machine, the force used to plunge the tools may range from 5000 to 8000 N which is currently beyond the capability of most robots. However, the capacity of robotic manipulators is increasing, so low force friction stir processing is becoming feasible. The ability of the robot arm to apply a controlled force that is normal to a 3-dimensional surface without the need to reorient the workpiece makes it a very useful tool for FSP of complex components. In this analysis, a robot arm with a capacity of 2500 N is used to improve the surface properties of nickel aluminum bronze (NAB) using low force FSP. Multiple passes were applied to the surface of the test sample for a more consistent spread of the stir zone. The sample was then microhardness tested and demonstrated a 62 pct increase in surface hardness. Cavitation erosion testing of the original and processed surfaces was also performed as per ASTM G-32. The erosion rate of the processed NAB sample was 44 pct of the rate experienced by the original cast NAB sample. Finally, the corrosion potentials of FSP NAB were measured at 45 mV less anodic than the unprocessed material, indicating that the processed material is more noble relative to the cast NAB sample. Robotic friction stir processing (FSP) has not been widely researched to date. This is perhaps due to the limited force capabilities of industrial robots in comparison with dedicated commercial FSP equipment. When operating a FSP machine, the force used to plunge the tools may range from 5000 to 8000 N which is currently beyond the capability of most robots. However, the capacity of robotic manipulators is increasing, so low force friction stir processing is becoming feasible. The ability of the robot arm to apply a controlled force that is normal to a 3-dimensional surface without the need to reorient the workpiece makes it a very useful tool for FSP of complex components. In this analysis, a robot arm with a capacity of 2500 N is used to improve the surface properties of nickel aluminum bronze (NAB) using low force FSP. Multiple passes were applied to the surface of the test sample for a more consistent spread of the stir zone.The sample was then microhardness tested and demonstrated a 62 pct increase in surface hardness. Cavitation erosion testing of the original and processed surfaces was also performed as per ASTM G-32. The erosion rate of the processed NAB sample was 44 pct of the rate experienced by the original cast NAB sample. Finally, the corrosion potentials of FSP NAB were measured at 45 mV less anodic than the unprocessed material, indicating that the processed material is more noble relative to the cast NAB sample.

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Section: Corrosion Testingsupporting

confidence: 83%

Section: B Microstructural Analysissupporting

confidence: 82%

Section: B Microstructural Analysismentioning

confidence: 99%

See 1 more Smart Citation

Feasibility Study of Low Force Robotic Friction Stir Process and its Effect On Cavitation Erosion and Electrochemical Corrosion for Ni Al Bronze Alloys

Ahmad

Pan

et al. 2014

Metall Mater Trans B

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“…According to the previous literature, the refined grains and homogeneous microstructure can improve the mechanical properties of the NAB alloy [13,14]. The corrosion resistance of FSP NAB alloy is also enhanced by the refined grains [15]. Song et al [16] found that FSP NAB suffers less severe attack than the as-cast NAB because FSP reduces the Volta potential difference among all the constituent phases in as-cast NAB.…”

Section: Introductionmentioning

confidence: 99%

Effect of Post Heat Treatment on the Microstructure and Microhardness of Friction Stir Processed NiAl Bronze (NAB) Alloy

Wang

et al. 2015

Metals

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NiAl bronze (NAB) alloy is prepared by using friction stir processing (FSP) technique at a tool rotation rate of 1200 rpm and a traverse speed of 150 mm/min. A post heat treatment is performed at the temperature of 675 °C. The effect of heat treatment on the microstructure and microhardness is studied. The results show that the microstructure of the FSP NAB alloy consists of high density dislocations, retained β phase (β′ phase) and recrystallized grains. When annealed at 675 °C, discontinuous static recrystallization (DSRX) takes place. The content of β′ phase gradually decreases and fine κ phase is precipitated. After annealing for 2 h, both the microhardness of the FSP sample in the stir zone (SZ) and the difference in hardness between the SZ and base metal decrease due to the reduction of the dislocation density and β′ phase, accompanying recrystallized grain coarsening. With further increasing of the annealing time to 4 h, the aforementioned difference in hardness nearly disappears.

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“…Contrary to the previous trend which showed lesser wear for the processed samples in dry condition, the trend is reversed in the sea-water test, the wear is more for the processed samples. The difference in trend observed in seawater tests can be explained if we consider the fact that the (electrochemical) corrosion of FSP processed alloy was found to be low as compared to the unprocessed sample as reported by Ni et al [12], their study being based on Electrochemical Impedance Spectroscopy (EIS) and on the polarization curve. Ni et al [12] ascribes this to two reasons: (1) due to the increase in Gibbs Free Energy introduced by the Friction Stir Processing resulting in severe plastic deformation and residual stress in the processed samples, which was also reported in Refs.…”

Section: Methodsmentioning

confidence: 99%