Material removal operations play a pivotal role in the manufacture of key components, required for engineering systems to operate safely and efficiently under ever more advanced functional requirements and over extended life cycles. To further step up the loading capability of machined parts, fundamental understanding of how of machining-induced features can influence the performance of advanced materials under complex service conditions is necessary over finer temporal and spatial scales. As discussed in Part I of this review, when engineering surfaces are generated by material removal processes, a wide range of physical mechanisms (e.g. mechanical, thermal, chemical and their combinations) drive the characteristics of workpiece surface integrity. In Part II of this review, the interplay between the metallurgical and micro-mechanical condition induced by material removal processes and their in-service response will be thoroughly explored, by a critical analysis of the state-of-the-art in the field. Specifically, attention is focused on recent advances made towards the understanding of the mechanisms determining the resistance of machined surface to fatigue crack nucleation (Section 2), corrosion and stress-corrosion cracking (Section 3), and wear (Section 4). Furthermore, the impact of relevant post-machining treatments on the in-service behaviour of machined surfaces is analysed, and the possible strategies for the enhancement of the functional performance of machined surfaces are presented (Section 5). Finally, the current research gaps and the prospective challenges in understanding the in-service behaviour of machined surfaces are critically discussed, providing an interpretation of the possible directions of future scientific development of this field.

Surface integrity in metal machining - Part II: Functional performance

NiTi shape memory alloys (SMAs) are used in a broad range of biomedical applications because of their unique properties including biocompatibility and high corrosion and wear resistance as well as functional properties such as superelasticity and the shape memory effect. The combination of SMAs and additive manufacturing can lead to revolutionary changes to the uses of SMAs in the biomedical industry. This article discusses the potential biomedical applications of NiTi that benefit from the AM process. We share the lessons learned in processing NiTi alloys with a focus on the laser powder bed fusion (LPBF) technique. The manufacturability, build quality, stable phases and transformation temperatures, microstructure, thermomechanical properties, microstructure tailoring, and functional properties of NiTi alloys produced via AM processing are reviewed. Current challenges such as expanding the process window, controlling the chemistry, and the performance and property responses are discussed, and potential opportunities including alloy design are discussed.

Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Ever-growing needs in pipeline welding relating to quality, frequent usage of advanced, heat-sensitive, and corrosion-resistant materials alongside high production costs encourage the evaluation of...

Assessment of weld bead geometry in modified shortcircuiting gas metal arc welding process for low alloy steel

Nowadays, the extensive use of glass-based materials for biomedical, micro-fluidic, and MEMS applications grabbed great attention. The use of glass substrate for the above-said applications require...

Impact of gas film thickness on the performance of RM-ECDM process during machining of glass

Tribodynamic studies of textured gearsets lubricated with fresh and MoS2 blended greases

In case of lightly loaded radial ball bearings, failure mechanisms other than fatigue such as smearing of raceways due to increased frictional torque and vibrations often prevail. Hence, attempts have been made herein for reducing the frictional torque and minimizing the vibrations of a radial deep groove ball bearing employing surface textures at the inner race. Nanosecond pulsed laser was used to create texture (involving micro-dimples having different dimple area density) on the inner race of test bearings. Using an in-house developed test rig, frictional torque and vibrational parameters were measured at different speeds and light loads (i.e. in vicinity of 0.01C, where C is dynamic load capacity of radial ball bearing). Significant reduction in frictional torque and overall vibrations were found in the presence of micro-dimples on inner race at light loads irrespective of operating speeds. Even without satisfying the minimum load needed criteria for the satisfactory operation, substantial reduction in smearing marks was found on the races of textured ball bearings in comparison to conventional cases.

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An exploration of frictional and vibrational behaviors of textured deep groove ball bearing in the vicinity of requisite minimum load

Improvement of Deep Groove Ball Bearing’s Performance Using a Bionic Textured Inner Race

Nickel-Titanium (Nitinol) alloy is one of the shape memory alloys with potential applications in biomedical and aerospace industries. However, long-term deployment of nitinol-based alloys in fluid ...

Optimization of laser parameters for improved corrosion resistance of nitinol

The tribological and vibrational behaviors of conventional and textured spur gear pairs were experimentally explored under fully flooded and starved lubrication conditions at different operating pa...

K. E. Ch. Vidyasagar

Papers

An exploration of frictional and vibrational behaviors of textured deep groove ball bearing in the vicinity of requisite minimum load

Improvement of Deep Groove Ball Bearing’s Performance Using a Bionic Textured Inner Race

Optimization of laser parameters for improved corrosion resistance of nitinol

Tribodynamic studies of textured gearsets lubricated with fresh and MoS2 blended greases

Tribological and Vibration Studies of Textured Spur Gear Pairs under Fully Flooded and Starved Lubrication Conditions