Titanium and its alloys have been used extensively in a wide variety of implant applications, such as artificial heart pumps, pacemaker cases, heart valve parts, and load-bearing bone or hip joint replacements or bone splints. This article discusses the properties of titanium and its alloys and presents a list of titanium-base biomaterials. Titanium components are produced in wrought, cast, and powder metallurgy (PM) form. The article describes forging, casting, and heat treating of titanium alloys for producing titanium components. Typical mechanical properties of titanium biomedical implant alloys are listed in a tabular form. The article presents an overview of the surface-modification methods for titanium and its alloys implants. It concludes with a section on biocompatibility and in vivo corrosion of titanium alloys.

This article tabulates materials that are known to have been used in orthopaedic and/or cardiovascular medical devices. The materials are grouped as metals, ceramics and glasses, and synthetic polymers in order. These tables were compiled from the Medical Materials Database which is a product of ASM International and Granta Design available by license online and as an in-house version. The material usage was gleaned from over 24,000 U.S. Food and Drug Administration (USFDA), Center for Devices and Radiological Health, Premarket notifications (510k), and USFDA Premarket Approvals, and other device records that are a part of this database. The database includes other material categories as well. The usage of materials in predicate devices is an efficient tool in the material selection process aiming for regulatory approval.

Bearing in mind the three-legged stool approach of device design/manufacturing, patient factors, and surgical technique, this article aims to inform the failure analyst of the metallurgical and materials engineering aspects of a medical device failure investigation. It focuses on the device "failures" that include fracture, wear, and corrosion. The article first discusses failure modes of long-term orthopedic and cardiovascular implants. The article then focuses on short-term implants, typically bone screws and plates. Lastly, failure modes of surgical tools are discussed. The conclusion of this article presents several case studies illustrating the various failure modes discussed throughout.

The biocompatibility of a material relates to its immunological response, toxicity profile, and ability to integrate with surrounding tissue without undesirable local or systemic effects on a patient. This article underscores the transformation of the medical device design ecosystem engaged as an integral part of the device ecosystem. It discusses the applications of biomaterials, including orthopedic, cardiovascular, ophthalmic, and dental applications. The article describes four major categories of biomaterials such as metals, polymers, glass and ceramics, and composites. A discussion on natural materials, nanomaterials, and stem cells is also provided. The article concludes with examples of biomaterials applications, such as endovascular devices, knee implants, and neurostimulation.

Titanium has been recognized as an element with good mechanical and physical properties, alloying characteristics, and corrosion resistance. Providing an outline of general characteristics and types of titanium alloys, this article discusses the contemporary technology of titanium along with its market developments. It also discusses the application of titanium and titanium alloys in corrosive environments and in aerospace and automotive industries. The article describes the developments in titanium processing and materials technologies, which include the development of sponge production and melting processes, oxide dispersion-strengthened alloys by powder metallurgy techniques, titanium-base intermetallic compounds, and titanium-matrix composites.

The human internal environment plays a vital role in the friction and wear of implants and prosthetic devices. This article describes the tribological/wear behavior of implants. It discusses the classification of active tribological pairs, namely, amphiarthosis joints and diarthosis joints. The article details the classification of total knee replacement, depending on the type of mechanical stability, including nonconstrained knee replacement, semiconstrained knee replacement, and constrained knee replacement. It also discusses the classifications of passive tribological pairs, namely, total disc replacement in the spine, dental implants, and temporomandibular joint. It describes the various testing methods for characterizing the implant materials used in hip, knee, spine, and dental applications. The article also describes the typical standards used for testing wear behavior of tribological pairs, namely, hip-wear simulation standards, knee-wear simulation standards, and spinal disc-wear simulation standards.

This article discusses the generic features of impact wear on metals, ceramics, and polymers. It describes normal impact wear and compound impact wear, as well as the features of impact wear testing apparatus such as ballistic impact wear apparatus and pivotal hammer impact wear apparatus. Most mechanical components continue to be functional beyond the zero wear limit, and their usefulness is normally connected with the loss of a specific depth of material. The article reviews the zero impact wear model and some measurable impact wear models. It presents a case study illustrating the impact of wear failure on automotive engine inlet valves and seat inserts.

Impact or percussive wear is defined as the wear of a solid surface that is due to percussion, which is a repetitive exposure to dynamic contact by another body. Impact wear, however, has many analogies to the field of erosive wear. The main difference is that, in impact wear situations, the bodies tend to be large and contact in a well-defined location in a controlled way, unlike erosion where the eroding particles are small and interact randomly with the target surface. This article describes some generic features and modes of impact wear of metals, ceramics, and polymers. It discusses the processes involved in testing and modeling of impact wear, and includes two case studies.

Zirconium and hafnium surfaces require cleaning and finishing for reasons such as preparation for joining, heat treatment, plating, forming, and producing final surface finishes. This article provides information on various surface treatment processes, surface soil removal, blast cleaning, chemical descaling, pickling or etching, anodizing, autoclaving, polishing, buffing, vapor phase nitriding, and electroplating. Applications of these surface treatment processes are also reviewed.

Biomaterials are the man-made metallic, ceramic, and polymeric materials used for intracorporeal applications in the human body. This article primarily focuses on metallic materials. It provides information on basic metallurgy, biocompatibility, chemistry, and the orthopedic and dental applications of metallic biomaterials. A table compares the mechanical properties of some common implant materials with those of bone. The article also provides information on coatings, ceramics, polymers, composites, cements, and adhesives, especially where they interact with metallic materials.

Safety is an important consideration in all welding, cutting, and related work. This article discusses the basic elements of safety general to all welding, cutting, and related processes. It includes safety procedures common to a variety of applications. The most important component of an effective safety and health program is management support and direction. The article reviews the role of management, training, housekeeping, and public demonstrations in welding safety to minimize personal injury and property damage. It provides information on the safety measures for eye and face protection in various welding and cutting operations. Injuries and fatalities from electric shock in welding and cutting operations can occur if proper precautionary measures are not followed. The article discusses the electrical safety aspects to be considered for various welding and cutting operations.

This article discusses several aspects of biocompatibility of polymers, including the selection of a suitable polymer, specific use of a material, contact of polymer on body site, and duration of the contact. It describes the factors influencing the biological response of the polymer from a biocompatibility perspective. These include raw materials, the manufacturing process, cleaning and sterilization processes, and biodegradation and biostability. The article reviews the general testing methods of polymers, such as chemical, mechanical and thermal. It concludes with a section on the guidance, provided by the regulatory authorities, on the biocompatibility testing of polymers and polymer-containing devices that can aid in selecting the right analysis.

Structural applications for advanced ceramics include mineral processing equipment, machine tools, wear components, heat exchangers, automotive products, aerospace components, and medical products. This article begins with an overview of the wear-resistant applications and the parameters affecting wear of ceramics, namely, hardness, thermal conductivity, fracture toughness, and corrosion resistance. The next part of the article addresses temperature-resistant applications of advanced ceramics. Specific applications of ceramic materials addressed include cutting tools, pump and valve components, rolling elements and bearings, paper and wire manufacturing, biomedical implants, heat exchangers, adiabatic diesel engines, advanced gas turbines, and aerospace applications.

Titanium and its alloys are used in various applications owing to its high strength, stiffness, good toughness, low density, and good corrosion resistance. This article discusses the applications of titanium and titanium alloys in gas turbine engine components, aerospace pressure vessels, optic-system support structures, prosthetic devices, and applications requiring corrosion resistance and high strength. It explains the effects of alloying elements in titanium alloys as they play an important role in controlling the microstructure and properties and describes the secondary phases and martensitic transformations formed in titanium alloy systems. Information on commercial and semicommercial grades and alloys of titanium is tabulated. The article also discusses the different grades of titanium alloys such as alpha, near-alpha alloys, alpha-beta alloys, beta alloys, and advanced titanium alloys (titanium-matrix composites and titanium aluminides).

Hardness testing equipment is important as all results from the induction equipment are graded by the hardness testing equipment. This article includes maintenance tips and points to consider regarding hardness test equipment, power supplies, controls, programmable logic controllers, computer systems, water cooling systems, fixtures and machines, air-operated or pneumatic devices, coils, and quench systems. It also presents simple rules that need to be applied while moving the equipment from one location to another.

This article focuses on the analysis of materials and mechanical- (or biomechanical-) based medical device failures. It reviews the failure analysis practices, including evidence receipt, cleaning, nondestructive examination, destructive examination, exemplars analysis, and device redesign. The article examines the common failure modes, such as overload, fatigue, corrosion, hydrogen embrittlement, and fretting, of medical devices. The failure analysis of orthopedic implants, such as permanent prostheses and internal fixation devices, is described. The article reviews the failure mechanisms in some of the more common medical device materials, namely, stainless steels, titanium alloys, cobalt-base alloys, and nitinol. It presents case histories with examples for failure analysis.

This article focuses on ceramics, glasses, glass-ceramics, and their derivatives, that is, inorganic-organic hybrids, in the forms of solid or porous bodies, oxide layers/coatings, and particles with sizes ranging from nanometers to micrometers, or even millimetres. These include inert crystalline ceramics, porous ceramics, calcium phosphate ceramics, and bioactive glasses. The article discusses the compositions of ceramics and carbon-base implant materials, and examines their differences in processing and structure. It describes the chemical and microstructural basis for their differences in physical properties, and relates the properties and hard-tissue response to particular clinical applications. The article also provides information on the glass or glass-ceramic particles used in cancer treatments.

Thermal spray coatings, along with certain proprietary sealants, are widely used in the paper manufacturing industry for corrosion and wear resistance and to impart special surface characteristics. This article discusses the steps involved in the paper manufacturing process. Most modern papermaking machines are based on variations of the Fourdrinier machine. The article describes four operational sections of the machine: forming, press, drying, and calendar. It provides an overview of the machine components where thermal spray coatings are used, namely, digesters, blow tanks, suction roll, center press rolls, yankee dryer rolls, calendar rolls, doctor/scalping blades, and cutting equipment.

This article focuses on the general methods and approaches from the perspective of a reconstruction analyst and includes discussions relevant to materials failure analysts at the incident scene. The elements of accident reconstruction are described. These have conceptual similarity with the principles for failure analysis of material incidents that are less complex than a large-scale accident. The article provides a brief review of some general concepts on the use of modeling which can be a very powerful tool for information pertaining to the reconstruction of an accident where the model can be a physical, mathematical, or logical representation of a physical system or process.

This article describes the extrusion process, which converts soft, plastic material into a particular form using an extruder, or screw conveyer. It discusses the two main types of plastic extruders, twin-screw and single-screw, estimation of extruder capacity, and design and operations (heating, cooling, downstream sizing, corrugating, and crossheading) of the screw, the most important component of any extruder. It discusses the shapes produced by screw extrusion and the types of extrusion products produced by extrusion processes, including blown-film extrusion, flat-film or sheet extrusion, chill-roll film extrusion, pipe or tube extrusion, wire and cable coverings, extrusion coating, and profile extrusion, and provides some discussion on multiple-screw extruders. The article describes the dimensional accuracy of extrusion products, and lists common defects that occur frequently in the extrusion process.