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Optical diagnostics for real-time monitoring and feedback control of metal additive manufacturing processes
Published in Adedeji B. Badiru, Vhance V. Valencia, David Liu, Additive Manufacturing Handbook, 2017
Glen P. Perram, Grady T. Phillips
A brief overview of some basic relationships between typical AM process parameters is presented below in the context of AFIT’s work with Ti-6Al-4V and cobalt chromium molybdenum alloys in a powder bed, SLM system. The basic thermal properties of the two alloy powders are provided in Table 20.1. Ti-6Al-4V, grade 5 titanium samples are 6% Al and 4% vanadium alloys. The cobalt chromium molybdenum samples in Table 20.1 are 59–65% Cr and 5–7% Mo. Thermal properties depend on particle size, with powders often sifted to provide an average particle diameter of d=10−50μm. The powder layer thickness is usually >100μm. Parts may be built on various substrates including aluminum and stainless steel.
Physical Vapor Deposition Coating Process in Biomedical Applications
Published in Sarbjeet Kaushal, Ishbir Singh, Satnam Singh, Ankit Gupta, Sustainable Advanced Manufacturing and Materials Processing, 2023
Sivaprakasam Palani, Elias G. Michael, Melaku Desta, Samson Mekbib Atnaw, Ravi Banoth, Suresh Kolanji
Pure titanium and extra-low interstitial (ELI) Ti-6Al-4V alloy are two of the most-used biological alloys for orthopedic implants (Nasker and Sinha 2018; Im 2020; Kaur and Singh 2019). In particular, the Ti-6Al-4V alloy possesses a variety of properties that make it appropriate for surgical implants, including a low elastic modulus, sufficient tensile and fatigue strengths, and biocompatibility. Despite the high mechanical capabilities of titanium-based alloys, the exposed surface of titanium-based implants is recognized for its poor tribological qualities (Raval et al. 2019). Various problems have been observed that have limited the long-term usage of Ti-based implants, all of which have a significant effect on patient health and healthcare expenditures. Due to wear and corrosion, Ti-based implants, particularly Ti-6Al-4V alloys, leak metallic particles and ions into surrounding tissues. Metallic debris that is not excreted from the tissue causes health issues such as bone loss as a result of inflammatory reaction. Another major worry is the toxicity of liberated aluminum and vanadium ions, which are the primary cause of peripheral neuropathy, osteocalcin, and Alzheimer’s disease in the long run (Bernhardt et al. 2021). While titanium has good biomechanical qualities, most titanium implants fail after 10–15 years, necessitating re-surgery. To minimize certain biomechanical and biological function failure, it is vital to increase the quality and dependability of Ti-based implants. The titanium alloy’s surface must be changed to meet standard bio-medical application criteria in order to minimize harm to the human body.
Overview of Mechanical Behavior of Materials
Published in Heather N. Hayenga, Helim Aranda-Espinoza, Biomaterial Mechanics, 2017
Radu Reit, Matthew Di Prima, Walter E. Voit
Seeking to improve upon the corrosion resistance and biocompatibility of the stainless steel alloys, commercially pure titanium was first used in a medical device in 1940 [12]. The greater conformity of titania (titanium oxide) to the bulk titanium over chromium oxide to stainless steel and the lack of nickel account for both improvements in biocompatibility and corrosion resistance. Commercially pure titanium has been used in at least 321 medical devices [11] in a number of different kinds of devices and applications. However, the mechanical properties of commercially pure titanium, as seen in Table 1.1, led to the development of titanium alloys to create materials with the biocompatibility/corrosion resistance of commercially pure titanium but with improved stiffness. The most common of the titanium alloys is Ti–6Al–4V, which as its name suggests contains 6% aluminum and 4% vanadium. This alloy is used in at least 1463 medical devices, demonstrating its wide appeal as a biomaterial [11]. The final titanium-based biomaterial of note is Nitinol, a near equiatomic alloy of titanium and nickel. Nitinol was developed in the 1960s [13] and while it exhibited unique shape memory properties, it was not until the late 1970s that it found a role as a biomaterial [14]. The shape memory properties of nitinol allow stents to self-expand instead of being balloon expanded (which brings a risk of blockage and stroke to the patient), allows for easier introduction through a catheter, and offers a nonoperative approach to surgeries [15,16]. While nitinol has been used in at least 547 medical devices [11], the addition of that much nickel to the titanium has led to concerns regarding corrosion resistance and nickel leaching of the alloy [17].
Estimation of machinability performance in wire-EDM on titanium alloy using neural networks
Published in Materials and Manufacturing Processes, 2022
Uma Maheshwera Reddy Paturi, Suryapavan Cheruku, Sriteja Salike, Venkat Phani Kumar Pasunuri, N.S. Reddy
Titanium alloy of grade-5 (Ti-6Al-4V) is a predominantly consumed material in the manufacturing sector. The extensive use of this material largely depends on its superior qualities. Ti-6Al-4V alloy is characterized by significant qualities like good strength, resistance to corrosion, chemical stability, fatigue resistance, excellent weldability, low thermal expansion, etc. makes it an ideal choice for consumers.[1] These properties enable its widespread application in the aerospace,[2–4] medical sector,[5,6] additive manufacturing,[7,8] chemical industries,[9] turbo machinery,[10] material science,[11] biomedical,[12,13] etc. But, Ti-6Al-4V alloy is difficult-to-machine with conventional turning and drilling operations due to high cutting temperatures, the stickiness of the alloy, and work hardening behavior. In addition, titanium alloys have a low elasticity in nature; which causes spring back and chatter during machining results in a deprived surface finish, dimensional imbalance, short cutting tool life, and elevated heat generation.[14,15] Thus, unconventional machining methods are the prime choice for machining of titanium alloys.[16–18]
Studies on chip morphology and modes of tool wear during machining of Ti-6Al-4V using uncoated carbide tool: application of multi-walled carbon nanotubes added rice bran oil as nanocutting fluid
Published in Machining Science and Technology, 2020
Thrinadh Jadam, Saurav Datta, Manoj Masanta
Titanium alloy (Grade 5) Ti-6Al-4V is a potential candidate for aerospace, automotive and biomedical applications. Diversified domain of successful application of Ti-6Al-4V is due to its excellent mechanical properties including low weight, high strength-to-weight ratio and outstanding corrosion resistance. However, this alloy is categorized as ‘difficult-to-cut’/‘difficult-to-machine’. This is because, machining of this alloy faces several challenges (Nouari and Makich, 2013; Sun et al., 2017; Hou et al., 2018; Kaplan et al., 2018; Jianxin et al., 2008). Due to hot strength and toughness of Ti-6Al-4V, magnitude of required cutting force is remarkably high; this in turn generates enormous heat. Poor thermal conductivity of Ti-6Al-4V (∼6.7 W/m.K) causes high-temperature evolution at the cutting zone. This alloy exhibits strong work-hardening tendency. At elevated cutting temperature, extreme chemical affinity of Ti-6Al-4V (toward tool material/Cobalt binder) causes aggressive tool wear (adhesion wear, diffusion, welding of work material over tool surface, etc.). Moreover, surface integrity of the machined work part appears very much disappointing due to unsatisfactory surface finish, presence of prominent feed marks, enormous chip sticking over the surface, and formation of work-hardened layer, just beneath the machined surface.
Improvement in performance of cryogenically treated tungsten carbide tools in face milling of Ti-6Al-4V alloy
Published in Materials and Manufacturing Processes, 2020
Abhineet Saini, B.S. Pabla, S.S. Dhami
Ti-6Al-4V is an important alloy of titanium family due to its exceptional mechanical properties. These include its high specific strength, high corrosion resistance, good biocompatibility and ability to retain strength at high temperatures.[8] This makes it suitable material for number of applications, including aerospace, automobile, biomedical, sports equipment and marine.[8] But, there are certain challenges in processing and fabrication of this material, which results in increased component cost and limits its use to certain demanding applications. Thus, there is a need of improvement in machinability characteristics of this material, as machining is the most important fabrication process for attaining precise shapes and dimensional accuracies. A number of techniques have been presented by researchers for tool life improvement of WC tools in Ti-6Al-4V machining.[9]