This article presents an overview of the developments in stainless steels made since the 1990s. Some of the new applications that involve the use of stainless steel are also introduced. A brief introduction to the various classes of stainless steels, their precipitate phases and the status quo of their production around the globe is given first. The advances in a variety of subject areas that have been made recently will then be presented. These recent advances include (1) new findings on the various precipitate phases (the new J phase, new orientation relationships, new phase diagram for the Fe–Cr system, etc.); (2) new suggestions for the prevention/mitigation of the different problems and new methods for their detection/measurement and (3) new techniques for surface/bulk property enhancement (such as laser shot peening, grain boundary engineering and grain refinement). Recent developments in topics like phase prediction, stacking fault energy, superplasticity, metadynamic recrystallisation and the calculation of mechanical properties are introduced, too. In the end of this article, several new applications that involve the use of stainless steels are presented. Some of these are the use of austenitic stainless steels for signature authentication (magnetic recording), the utilisation of the cryogenic magnetic transition of the sigma phase for hot spot detection (the Sigmaplugs), the new Pt-enhanced radiopaque stainless steel (PERSS) coronary stents and stainless steel stents that may be used for magnetic drug targeting. Besides recent developments in conventional stainless steels, those in the high-nitrogen, low-Ni (or Ni-free) varieties are also introduced. These recent developments include new methods for attaining very high nitrogen contents, new guidelines for alloy design, the merits/demerits associated with high nitrogen contents, etc.

Recent developments in stainless steels

Abstract The historical background, research development, and the state-of-the-art of finite time thermodynamic theory and applications are reviewed from the point of view of both physics and engineering. The emphasis is on the performance optimization of thermodynamic processes and devices with finite-time and/or finite-size constraints, including heat engines, refrigerators, heat pumps, chemical reactions and some other processes, with respect to the following aspects: the study of Newton's law systems, an analysis of the effect of heat resistance and other irreversible loss models on the performance, an analysis of the effect of heat reservoir models on the performance, as well as the application for real thermodynamic processes and devices. It is pointed out that the generalized thermodynamic optimization theory is the development direction of finite thermodynamics in the future.

Finite Time Thermodynamic Optimization or Entropy Generation Minimization of Energy Systems

Review on titanium and titanium based alloys as biomaterials for orthopaedic applications.

Silver, known in metallic form since antiquity, has very early been recognized by mankind for its antimicrobial properties, a phenomenon observed, for example, in the context of drinking water (a silver coin in a well), food (silver cutlery, water storage recipients), and medicine (silver skull plates, teeth). Silver compounds were also shown to be useful. For example, dilute solutions of silver nitrate served long, and still do in some countries, as antimicrobial ointment to be instilled into Published in \" \" which should be cited to refer to this work.

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Nanobio Silver: Its Interactions with Peptides and Bacteria, and Its Uses in Medicine

A review of modified DLC coatings for biological applications

The main aim of this work is to evaluate the effects of the plasma nitriding process on AISI M2 tool steel. In previous work, treatment time and temperature were varied to identify the treatment conditions for good wear behaviour. In the present work, the treatment time was fixed while temperature and gas pressure were varied. Samples were characterised by glow discharge optical spectroscopy, scanning electron microscopy, X‐ray diffraction, surface microhardness and wear test. The specimens nitrided at 400 and 900 Pa showed the best wear performance, which is possibly due to reduction of the friction coefficient and the low adhesive wear observed. Samples processed at 200 Pa showed spalling during the wear test, indicating a brittle surface.

The effects of plasma nitriding process parameters on the wear characteristics of AISI M2 tool steel

The stress distributions associated with frictionless and smooth surfaces in contact are rarely experienced in practice. Factors such as layers, friction, surface roughness, lubricant films, and third body particulate are known to influence the state of stress and the resulting rolling contact fatigue life. A numerical technique for evaluating the subsurface stresses arising from the two-dimensional sliding contact of two elastic bodies with real rough surfaces has been developed, where an elastic body contacts with a multi-layer surface under both normal and tangential forces. The presence of friction and asperities within the contact region causes a large, highly stress region exposed to the surface. The significance of these near-surface stresses is related to modes of surface distress leading to surface eventual failure (Mao et al., 1997).

Effect of Sliding Friction on Contact Stresses for Multi-Layered Elastic Bodies With Rough Surfaces

A numerical model for the two-dimensional dry sliding contact of two elastic bodies with real rough surfaces has been developed, where an elastic body contacts with a multi-layer surface under both normal and tangential forces The model uses surface profile data directly recorded with a stylus measuring instrument and it is suitable for use on a microcomputer Green's function for a unit normal load and a unit tangential load for the generalized plane strain problem are derived Verification of the accuracy of the model by reproduction of test case results is presented Contact pressure distribution for layers of varying coefficient of friction, thickness and elastic modulus is analyzed Presented as a Society of Tribologists and Lubrication Engineers paper at the STLE/ASME Tribology Conference in Klssimmee, Florida, October 8–11, 1995

A Numerical Model for the Dry Sliding Contact of Layered Elastic Bodies with Rough Surfaces

Titanium aluminides have low surface hardness and poor tribological properties, which could limit their applications in such areas where contact and wear are involved, e.g. valves in an auto-engine. In this study, a γ -based titanium aluminide has undergone a series of thermal oxidation processing to produce an oxide layer on the aluminide surface. The mechanical properties, the scratch resistance, the deformation and the damage behaviours of the oxide layer have been evaluated using nanoindentation and nanoscratch techniques. It has been found that the oxide layer on titanium aluminide surface is multi-layered oxide consisting of predominant TiO 2 and Al 2 O 3 . Due to increased surface hardness ( H ) and elastic modulus ( E r ) as well as reduced E r  /  H ratio, the surface treatment has improved the scratch resistance and micro-abrasive wear resistance of the titanium aluminide. The nanoscratch properties of the treated titanium aluminide have been correlated with the scratching load, the hardness and the E r  /  H ratio of the surface oxide layer.

T. Bell

Papers

The effects of plasma nitriding process parameters on the wear characteristics of AISI M2 tool steel

Effect of Sliding Friction on Contact Stresses for Multi-Layered Elastic Bodies With Rough Surfaces

A Numerical Model for the Dry Sliding Contact of Layered Elastic Bodies with Rough Surfaces

Nanoindentation and nanoscratch properties of a thermal oxidation treated γ-TiAl based alloy

Characterization and tribological performance of oxide layers on a gamma based titanium aluminide