Microstructure and corrosion behavior of laser processed NiTi alloy

Marattukalam, Jithin James; Singh, Amit Kumar; Datta, Susmit; Das, Mitun; Balla, Vamsi Krishna; Bontha, Srikanth; Kalpathy, Sreeram K.

doi:10.1016/j.msec.2015.07.067

Cited by 94 publications

(36 citation statements)

References 17 publications

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“…The average microhardness is more for NiTi samples with a higher level of Ti content, and it is due to the formation of NiTi 2 that results in the increased hardness [51,92]. These values are reported by According to Marattukalam et al [53], the hardness of LENS processed NiTi (Ni50.05Ti) is increased by the adoption of higher laser powers. However, it can be observed that the resulting hardness of NiTi parts is decreased marginally by increasing scanning velocity (See figure 27a).…”

Section: Hardness and Corrosion Resistancementioning

confidence: 76%

“…The associated lower rate of cooling (dT/dt) leads to the formation of coarser grains (See figure 10) [46,73,76]. Several groups [33,46,53] studied the effect of laser power and scanning speed on the grain size of AM NiTi, as presented in table 3. The results indicate that the grain sizes are increased with higher laser power while scanning speed seems not to have a significant effect on the grains width and length.…”

Section: Effect Of Parameters With Epitaxial Solidificationmentioning

confidence: 99%

“…The increased microhardness of NiTi resulted from increased energy input (i.e., higher laser power and lower scanning speed) also enhances the corrosion resistance [53]. The reason is that the increased energy input results in the reduction of grain boundaries (i.e., discontinuities in the regular atomic structure of a crystal).…”

Section: Hardness and Corrosion Resistancementioning

confidence: 99%

“…The reason is that the increased energy input results in the reduction of grain boundaries (i.e., discontinuities in the regular atomic structure of a crystal). Grain boundaries are the most favorite place for the precipitates and impurities nucleation, and the reduction of grain boundaries obviously decrease the corrosion rate [53,93,94].…”

Section: Hardness and Corrosion Resistancementioning

confidence: 99%

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Fabrication of NiTi through additive manufacturing: A review

Elahinia

Moghaddam

Andani

et al. 2016

Progress in Materials Science

582

210

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Nickel-titanium (NiTi) is an attractive alloy due to its unique functional properties (i.e., shape memory effect and superelasticity behaviors), low stiffness, biocompatibility, damping characteristics, and corrosion behavior. It is however a hard task to fabricate NiTi parts because of the high reactivity and high ductility of the alloy which results in difficulties in the processing and machining. These challenges altogether have limited the starting form of NiTi devices to simple geometries including rod, wire, bar, tube, sheet, and strip. In recent years, additive manufacturing (AM) techniques have been implemented for the direct production of complex NiTi such as latticebased and hollow structures with the potential use in aerospace and medical applications. It worth noting that due to the relatively higher cost, AM is considered a supplement technique for the existing. This paper provides a comprehensive review of the publications related to the AM techniques of NiTi while highlighting current challenges and methods of solving them. To this end, the properties of conventionally fabricated NiTi are compared with those of AM fabricated alloys. The critical steps toward a successful manufacturing such as powder preparation, optimum laser parameters, and fabrication chamber conditions are explained. The microstructural characteristics and structural defects, the influencing factors on the transformation temperatures, and functional properties of NiTi are highlighted to provide and overview of the influencing factors and possible controlling methods. The mechanical properties such as hardness and wear resistance, compressive behaviors, fatigue characteristics, damping and shock absorption properties are also reported. A case study in the form of using AM as a promising technique to fabricate engineered porous NiTi for the purpose of creating a building block for medical applications is introduced. The paper concludes with a section that summarizes the main findings from the literature and outlines the trend for future research in the AM processing of NiTi.

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Section: Hardness and Corrosion Resistancementioning

confidence: 76%

Section: Effect Of Parameters With Epitaxial Solidificationmentioning

confidence: 99%

Section: Hardness and Corrosion Resistancementioning

confidence: 99%

Section: Hardness and Corrosion Resistancementioning

confidence: 99%

See 2 more Smart Citations

Fabrication of NiTi through additive manufacturing: A review

Elahinia

Moghaddam

Andani

et al. 2016

Progress in Materials Science

582

210

View full text Add to dashboard Cite

show abstract

“…The corrosion potential reflects the thermodynamic characteristics of the system. The lower the corrosion current density, the better the corrosion resistance and the lower the corrosion potential, the bigger the corrosion tendency of the materials . It can be seen from Table that the corrosion current density of Q235M is lower than that of Q235 and the corrosion potential is more positive than that of Q235.…”

Section: Resultsmentioning

confidence: 95%

Effects of rare earth elements on corrosion behaviors of low‐carbon steels and weathering steels

Liu

Lian

Liu

et al. 2019

Materials & Corrosion

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The effects of rare earth elements on the corrosion properties of low‐carbon steel and weathering steel were investigated. To elucidate the roles of rare earth elements (Ce and La) and the corrosion behavior of steels, salt spray tests, electrochemical techniques, X‐ray diffractometer, scanning electron microscopy, Electron Probe Micro Analysis (EPMA), and Auger Electron Spectroscopy (AES) were conducted. The results showed that the addition of rare earth elements enhances the corrosion resistance of both low‐carbon steels and weathering steels, indicated by lower corrosion current density and salt spray corrosion rate after rare earth alloying. On the one hand, rare earth elements modify the morphology of inclusions and thus slow down the micro‐area electrochemical corrosion, which improves the electrochemical corrosion resistance of these two steels. On the other hand, rare earth atoms tend to segregate toward the interface between the rust layer and the matrix. Hence, salt spray corrosion resistance is improved due to the enhancement of adhesion and compactness of the rust by the addition of rare earth elements.

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