NiTi shape memory alloys (SMAs) are extensively used in various significant areas such as aerospace industries, biomedical sector, automobile industries, and robotics field because of their inherent properties, namely, shape memory effect and superelasticity. Nevertheless, the machining of these alloys is a problematic task by conventional machining practices because of various difficulties such as strain hardening, tool failure, high machining time, and poor surface quality. In recent years, researchers have explored various advanced/unconventional machining processes to surmount these challenges and improve the performance characteristics of NiTi SMAs. Wire electrical discharge machining (WEDM) is an effective and reasonable alternative to machine these hard-to-machine alloys among the other available advanced machining processes. A brief overview, characteristics, applications, and conventional machining of NiTi SMAs have been incorporated in this study. This review article provides substantial insight into the various aspects of surface integrity (SI) for NiTi SMAs using WEDM. The current study highlights literature review on the research work accomplished so far in the domain of SI aspects for NiTi-based SMAs, namely, surface characteristics, react layer, phase analysis, elemental composition, micro-hardness, shape recovery ability, and residual stress in WEDM.

Electrical discharge machining (EDM) is a method capable of modifying the microstructure of metal surfaces. Here, we present a predictive computer supported model of the roughness generated on the surface by this process. EDM is a stochastic process, in which charge generated between a metallic substrate and an electrode creates impacts, and thus is suitable for modeling through iterative simulations. The resulting virtual, modified surface structures were evaluated for roughness. Curvatures were analyzed using Abbott-Firestone curves. Three radii of impacts (10, 20, 30 μm) and two values for the depth to radius ratio (0.1, 0.3) were used as input parameters to compute a total of six simulations. It was found that the roughness parameters followed an inverse exponential trend as a function of impact number, and that the strongly concave curvatures reached equilibrium at an earlier impact number for lower depth to radius ratios.

Considering their distinctive properties, titanium alloys are used in foremost industries, including the aeronautic, automotive and biomedical industries. The reduced machinability of titanium alloys is due to their low thermal conductivity and high plasticity behavior. In the biomedical sector, one of the most studied alloys is Ti-6Al-4V. In the case of the Ti-6Al-7Nb alloy, scarce investigations are identified, related to machinability studies. The machining of Ti-6Al-7Nb alloy requires the development of new tools with higher properties, which provide better performance. The objective of this study is to present the experimental results related to a novel ceramic cutting tool, in terms of cutting tool life and productivity, in the machining of Ti-6Al-7Nb alloy. A turning operation of a 25 mm diameter bar was performed; the cutting speed was varied in three levels. The results showed the high performance of this type of tools, from the point of view of machinability. The values of the obtained cutting forces are found in the ranges reported by the consulted literature using ceramic tools. The surface roughness values were considered appropriate, taking into account that the tool is recommended for roughing and semi-finishing operations. The most relevant results were obtained in terms of productivity, considering that the performance is 2.53 times higher than the presented in similar works.

Large strain extrusion machining (LSEM) emerges as an innovative severe plastic deformation method of fabricating ultrafine grained materials. However, substantial heat generated during LSEM would sacrifice the mechanical properties of materials. Cryogenic temperature (CT) LSEM is put forward to overcome this shortcoming. The Al 7075 was processed by cryogenic and room temperature (RT) LSEM to investigate their comparative effects on mechanical and microstructural properties. Results indicate that the chip morphology of CT LSEM is featured with better integrity. Grains are refined to less than 200 nm by CT LSEM. A more complicated microstructure with high dislocation density is observed in the CT LSEM specimens. The hardness of cryogenic and RT LSEM specimens increases with the compression ratio and reaches the highest values of 187HV and 170HV, respectively. Dislocation strengthening is the main contributor, accounting for the higher hardness of CT LSEM specimens.

The Connecticut (CT) State Colleges and Universities’ College of Technology (COT) and its Regional Center for Next Generation Manufacturing (RCNGM), a National Science Foundation (NSF) Center of Excellence, educate manufacturing technicians with necessary skills as needed by the manufacturing industry. The COT-RCNGM continuously broadens its partnerships with other community colleges, high schools and industry in New England and at the national and international levels to provide support and expertise to both students and educators in advanced manufacturing programs. The COT was founded in 1995 through state legislation to create and implement seamless pathways in engineering and technology. This system-wide collaboration of all twelve CT public community colleges, including seven state-of-the-art Advanced Manufacturing Technology Centers (AMTC) at CT’s community colleges; eight public and private universities; technical high and comprehensive high schools; and representatives from industry, including the CT Business & Industry Association (CBIA) which represents 10,000 companies. The pathways have multiple points of entry and exit for job placement and stackable credentials for degree completion, including national certifications that have increased enrollments and created program stability.

The COT is led by the Site Coordinators Council that meets monthly and consists of faculty and deans from all COT educational partners and representatives from industry and government. The Council identifies and reviews new programs, concentrations, and certificates based on industry needs and creates seamless articulated pathways. Final approval is often completed within three months for immediate implementation, allowing a timely response to workforce needs. The COT-RCNGM partners with CBIA to conduct a biannual survey of manufacturing workforce needs in CT. Educators use the survey to identify curricular needs and support funding proposals for educational programs. Asnuntuck Community College, the original AMTC, was able to use industry data from the survey to help create new programs. The RCNGM partners with other NSF grants and entities such as the National Network for Manufacturing Innovation (NNMI). The COT-RCNGM produced DVDs profiling students who have completed COT programs and work in CT manufacturing companies. The Manufacture Your Future 2.0 and the You Belong: Women in Manufacturing DVDs are distributed nationally to increase knowledge of career opportunities in manufacturing. Finally, the COT-RCNGM organizes the Greater Hartford Mini Maker Faire that brings together community members of all ages and backgrounds to share projects that promote interest in STEM fields. Participation in the Maker Movement led to involvement in a national network of Maker Faire organizers including a meeting at the White House where one organizer from each state was invited to attend and discuss the national impact of Makers.

The large strain extrusion-machining process has been used to refine the microstructure in a Titanium alloy (Ti–6Al–4V). The unconstrained cutting or machining of Ti–6Al–4V entails the formation of shear localized chips at nearly all cutting speeds, thereby hindering the use of extrusion-machining to produce fine-grained materials. The present effort attempts to suppress shear localization by the suitable modification of texture in Ti–6Al–4V through the cold-rolling process prior to extrusion-machining. Ti–6Al–4V plates were cold rolled to 30, 40, 45, and 47% thickness reductions. These textured plates were extrusion machined using a suitably designed fixture leading to fine-grained continuous foils with increased hardness. Microscopy has revealed that the suppression of shear localization in the foils produced from plates which are cold rolled to more than 40% of thickness reduction is triggered by texture formation. For thickness reductions slightly lower than 40% (e.g., 30%), suppression can be achieved only by a combination of texture and extrusion.

We demonstrate anisotropic, vertical deep etching of graphite and densely packed carbon nanotube (CNT) thick layer beyond the micrometer scale, which representing the first step toward nanocarbon bulk micromachining. This micromachining process is compatible with standard lithography and therefore allows the fabrication of graphite and CNT architectures with 1 μm lateral resolution and up to 10 μm scale depth.

Simple shear deformation via hybrid cutting-extrusion is used to produce continuous electrical steel sheet from a commercial high-silicon (nominal 4 wt%) iron alloy of poor workability in a single deformation step, a fundamentally different route from the multi-step processing of rolling and annealing currently in use. The shear texture created in the sheet is found to be quite different from that produced by rolling. The magnetic properties of the shear-textured Fe–Si sheet are measured using closed-circuit permeametry and compared with those from sheet produced by rolling of the same alloy and a commercial non-grain-oriented sheet of similar composition. Properties compared include maximum relative permeability, induction, coercivity, and hysteresis loss. The results are interpreted in terms of microstructure, texture, and composition. A unit cell representation of the shear texture components is introduced that relates the expected orientation of easy magnetization directions with the sheet axes.

This article summarizes recent research on laser-based processing of two-dimensional (2D) atomic layered materials, including graphene and transition-metal dichalcogenides (TMDCs). Ultrafast lasers offer unique processing routes that take advantage of distinct interaction mechanisms with 2D materials to enable extremely localized energy deposition. Experiments have shown that ablative direct patterning of graphene by ultrafast lasers can achieve resolutions of tens of nanometers, as well as single-step pattern transfer. Ultrafast lasers also induce non-thermal excitation mechanisms that are useful for the thinning of TMDCs to tune the 2D material bandgap. Laser-assisted site-specific doping was recently demonstrated and ultrafast laser radiation under ambient air environment could be used for the direct writing of high-quality graphene patterns on insulating substrates. This article concludes with an outlook on developing further advanced laser processing with scalability, in situ monitoring strategies, and potential applications.

Machining is an important technological process in many areas of industry. The efficiency of machining determines the quality of many industrial products. Machining efficiency and cost depend on the properties, strength, and microstructure of the machining materials. One of the promising ways to increase the reliability and wear resistance of machining tools is the development and use of hierarchical machining materials. In the area of machining materials, designed typically as binder/reinforcement composites, hierarchical structures are realized as lower-scale secondary reinforcements (such as nanoparticles in the binder, or polycrystalline, aggregate-like reinforcements, also at several scale levels). Such materials can ensure better productivity, efficiency, and lower costs of drilling, cutting, grinding, and other technological processes. This article reviews the main groups of hierarchical machining materials and their performance.

Potassium dihydrogen phosphate (KDP) is an important nonlinear optical crystal material for light frequency converters and Pockels photoelectric switches in laser systems. However, KDP is apt to fracture, is deliquescent, and can suffer from microstructural changes under a temperature variation. As such, KDP has been one of the most difficult-to-handle materials, but its properties have not been well understood. This paper aims to explore the mechanical properties of KDP crystals in detail with the aid of the nanoindentation technique using a Berkovich diamond indenter. It was found that the mechanical properties of KDP can be easily altered by machining-induced subsurface damage. It was also discovered that a KDP crystal is a visco-elasto-plastic material during micro/nanoscale deformation, although it is very brittle macroscopically.

The aim of this study is to prevent cracks in large foam bodies prepared by thermo-foaming of alumina powder dispersions in molten sucrose. Cracks initiate in the binder burnout stage during which the bodies undergo shrinkage in the range of 32–49 vol% depending on sucrose content. Intermediate pyrolysis of the sucrose polymer binder prevents the cracking of large foam bodies as the carbon produced by pyrolysis binds the alumina particles during the initial stage of shrinkage and provides adequate strength to withstand the internal stresses produced during the pyrolysis and subsequent carbon burnout. The carbon bonded alumina foam bodies obtained after pyrolysis do not show any visible cracks during subsequent carbon burnout and sintering because the alumina particles establish a firm network with each other due to particle drag and rearrangement during pyrolysis of the sucrose polymer binder as evidenced from microstructure analysis. The carbon bonded alumina foam bodies show high compressive strength (2–1.3 MPa) and are amenable to machining operations such as milling and drilling without cracking.

We show that alloying with rare earth metals (REMs) can dramatically improve the machineability of a range of titanium alloys, even though the REM is not incorporated in the alloy matrix. The mechanism for this is that under cutting, shear bands are formed within which the nano-precipitates of REM are shear mixed. This lowers the melting point such that the mechanism of deformation changes from dislocation mechanism to localised amorphisation and shear softening. The material then fractures along the thin, amorphous shear-band. Outside the shear band, the REM remains as precipitates. The new alloys have similar mechanical properties and biocompatibility to conventional materials.

The main purpose of coatings is to increase the lifetime of cutting tools, to perform continuous and economical material removal process, reducing the frequency of sharpening or replacement of the tool, which contributes to increase quality of product. Therefore, hafnium nitride (HfN) single layer coatings were deposited on High-speed steel by Magnetron Sputtering physical vapour deposition (PVD). The machining on AISI 1020 steel samples were carried out in a computer numerical control (CNC) machine, using coated and uncoated tools, the temperature of the different components were measured (steel bar and tool), due to continuous temperature measurement help to predict tool wear and the quality of finished piece [1] . In order to evaluate wear resistance and performance, not only temperature data were compared, the tool wear morphological analysis for flank wear was carried using Scanning Electron Microscopy (SEM), and work pieces roughness were checked through their surfaces in an Atomic Force Microscopy (AFM). In most of the parameters evaluated differences between the tools were identified, and results reveals that on HfN coating, occurs less wear, due the proportionality between the energy transfer and the tool deterioration, also the coating improves surface finish of the machined part; all of them are reflected in changes on process temperatures. The use of single layer HfN coating on cutting tools could increase their lifetime, improve the quality of the work piece, and even reduce process time and cost.

The aerospace and automotive industries demand the development of new manufacturing processes. The productivity during machining of very flexible aerospace and automotive aluminum components is limited for self-excited vibrations. New solutions are needed to suppress vibrations that affect the accuracy and quality of the machined surfaces. Rejection of one piece implies an increase in the manufacturing cost and time. This paper is focused on the design, manufacturing and characterization of a magnetorheological damper. The damper was attached to a thin-floored component and a magnetic field was controlled in order to modify the damping behavior of the system. The dynamics of the machining process was developed by considering a three-degree-of-freedom model. This study was experimentally validated with a bull-nose end milling tool to manufacture monolithic parts with thin wall and thin floor. Experimental tests and characterization of the magnetorheological damper permitted to improve the surface finish and productivity during the machining of thin-floored components. A further aim of this paper was to develop a rheological damper by using magnetorheological fluids (MR) to change the thin floor rigidity with voltage. The stability of the milling process was also analytically described considering one, two or three degrees of freedom, using a mathematical integration model based on the Enhanced Multistage Homotopy Perturbation Method (EMHPM).

Tribology is a phenomenon concerning the relative motion between at least two amalgamating surfaces. In the machining process, surface roughness is the most important element for studying this occurrence, which contributes to the evaluation of part quality. This paper will provide detailed analysis for better understanding of tribological during the machining process of Inconel 718 alloy using a multi-layer TiAlN/AlCrN-coated carbide ball end inserted in dry cutting condition. The analysis focused on the relationship of tool wear with cutting temperature, cutting force, and surface integrity. Results found that the cutting temperature increased around 7.5% and surface roughness of machined surface improved about 10.3% when the cutting speed increased. Flaking at the rake face and notching at the flank face were determined as the main tool failures during milling Inconel 718. Furthermore, high friction between the tool–workpiece interfaces during machining was due to the build-up edge (BUE) formation that causes an alteration in microstructure at machine surface.

Engineering, whether in the form of product development or manufacturing processes, often drives the selection or creation of new materials in order to meet performance requirements. Conversely, development of new materials, or new ways to process materials, can lead to new engineering capabilities that, in turn, lead to new products or improved product performance. The interplay between materials and engineering is dynamic, ongoing, and critical to the success of many new products and industries. In this article, we take examples of this interplay from four technology companies in different industries developing widely different materials systems. Each example demonstrates the critical role that materials play in creating new products, new manufacturing methods, and even new design methodologies. Our examples come from polymer microfluidic devices, silicon- and nonsilicon-based microelectromechanical systems, and metals additive manufacturing.

Electrochemical micromachining (ECMM) with microtool electrodes is a promising method for microshaping bulk metallic glasses (BMGs) at room temperature. A key challenge is the control of the electrode reactions to impede the disturbing passive layer formation on machined surface regions. In the example case of a Fe-based glassy Fe65.5Cr4Mo4Ga4P12C5B5.5 alloy, it will be demonstrated that by using an aqueous electrolyte based on 0.1 M H2SO4 solution with up to 0.1 M Fe2(SO4)3 addition and by applying ultrashort voltage pulses, complex microstructures can be machined with high precision. Potentiodynamic polarization measurements reveal that the salt addition reduces the charge transfer resistance of the microtool and therefore, the negative bias potential effect. The free corrosion and passive state of the BMG workpiece are affected, but not the transpassive regime. Systematic ECMM studies were conducted to obtain optimum parameters for shaping complex lateral structures with very smooth and well-defined machining areas.

The carbon foams prepared by the thermo-foaming of dispersions of activated carbon (AC) powder of various average particle sizes (4.9 to 15 μm) in an aqueous sucrose resin were characterized. The stability of the wet foams increased with the decrease in the AC particle size as finer particles preferentially adsorbed on the air–resin interface. The particle agglomeration leading to the foam collapse was observed at lower AC powder to sucrose weight ratios with the finer powders. The cell size (0.33–2.34 mm), foam density (0.1151–0.2281 g/cm3), and compressive strength (0.16–2.77 MPa) of the carbon foams depend on the AC particle size as well as the AC powder to sucrose weight ratio. The thermal conductivity of the carbon foams (0.036–0.049 W m−1 K−1) was much lower than that of the vitreous carbon foams of similar densities. The foams were fire resistant and amenable to machining with the conventional machines and tool.

This paper discusses tensile testing of small samples of nanocrystalline Al6061-T6 alloy obtained from an unusual application of machining as a severe plastic deformation process. Ultrafine grained (UFG) shavings obtained from plane-strain cutting show higher hardness than the bulk material in agreement with existing literature. Application of restricted contact tools and extrusion-machining was explored to obtain shavings with minimum curvature to aid in tensile test specimen preparation. A novel method to prepare small tensile test specimens from these shavings has been described. During the tensile testing of UFG material, strains were measured using digital image correlation of natural speckles on the specimen. Specimens made from the UFG material had higher tensile strength and yield stress than the bulk, while ductility was lower. Lower values of Young's modulus were observed during the tensile testing of small specimens made from UFG as well as bulk material.