Research in stretchable electronics involves fundamental scientific topics relevant to applications with importance in human healthcare. Despite significant progress in active components, routes to mechanically robust construction are lacking. Here, we introduce materials and composite designs for thin, breathable, soft electronics that can adhere strongly to the skin, with the ability to be applied and removed hundreds of times without damaging the devices or the skin, even in regions with substantial topography and coverage of hair. The approach combines thin, ultralow modulus, cellular silicone materials with elastic, strain-limiting fabrics, to yield a compliant but rugged platform for stretchable electronics. Theoretical and experimental studies highlight the mechanics of adhesion and elastic deformation. Demonstrations include cutaneous optical, electrical and radio frequency sensors for measuring hydration state, electrophysiological activity, pulse and cerebral oximetry. Multipoint monitoring of a subject in an advanced driving simulator provides a practical example.

/pdf/rugged-and-breathable-forms-of-stretchable-electronics-with-5cb7g919h4.pdf

Rugged and breathable forms of stretchable electronics with adherent composite substrates for transcutaneous monitoring

Review of corrosive environments for copper and its corrosion inhibitors

Additive manufacturing of Cu-10Sn bronze

Maraging steels are used to produce tools by Additive Manufacturing (AM) methods such as Laser Metal Deposition (LMD) and Selective Laser Melting (SLM). Although it is well established that dense parts can be produced by AM, the influence of the AM process on the microstructure—in particular the content of retained and reversed austenite as well as the nanostructure, especially the precipitate density and chemistry, are not yet explored. Here, we study these features using microhardness measurements, Optical Microscopy, Electron Backscatter Diffraction (EBSD), Energy Dispersive Spectroscopy (EDS), and Atom Probe Tomography (APT) in the as-produced state and during ageing heat treatment. We find that due to microsegregation, retained austenite exists in the as-LMD- and as-SLM-produced states but not in the conventionally-produced material. The hardness in the as-LMD-produced state is higher than in the conventionally and SLM-produced materials, however, not in the uppermost layers. By APT, it is confirmed that this is due to early stages of precipitation induced by the cyclic re-heating upon further deposition—i.e., the intrinsic heat treatment associated with LMD. In the peak-aged state, which is reached after a similar time in all materials, the hardness of SLM- and LMD-produced material is slightly lower than in conventionally-produced material due to the presence of retained austenite and reversed austenite formed during ageing.

Comparison of Maraging Steel Micro- and Nanostructure Produced Conventionally and by Laser Additive Manufacturing.

Effect of welding speed on microstructure and mechanical properties of friction stir welded copper

Copper was among the first metals to be put into utilitarian service. The Unified Numbering System (UNS) is the accepted alloy designation system in North America for wrought and cast coppers and copper alloys. Identification is by five-digit numbers preceded by the letter C. Preferred marine alloys include copper nickels, which exhibit the highest corrosion and erosion resistance among copper metals, and also offer relatively high strengths, and aluminum bronzes, which are stronger still, as well as ultrahigh-strength beryllium copper, inhibited aluminum brass, phosphor bronzes, arsenical admiralty brass, and nickel silvers. Copper alloys that perform well in seawater are also often acceptable for use with industrial and process. Copper casting alloys are widely used in the manufacture of plumbing, electrical, and mechanical products and for bearings and industrial valves and fittings. Copper nickels, aluminum bronzes, silicon bronzes, manganese bronzes, and tin and phosphor bronzes should be considered for such environments.


Keywords:

copper alloys;
marine alloys;
Unified Numbering System (UNS)

4 Copper and Copper Alloys

Copper was among the first metals to be put into utilitarian service. The Unified Numbering System (UNS) is the accepted alloy designation system in North America for wrought and cast coppers and copper alloys. Identification is by five-digit numbers preceded by the letter C. Preferred marine alloys include copper nickels, which exhibit the highest corrosion and erosion resistance among copper metals, and also offer relatively high strengths, and aluminum bronzes, which are stronger still, as well as ultrahigh-strength beryllium copper, inhibited aluminum brass, phosphor bronzes, arsenical admiralty brass, and nickel silvers. Copper alloys that perform well in seawater are also often acceptable for use with industrial and process. Copper casting alloys are widely used in the manufacture of plumbing, electrical, and mechanical products and for bearings and industrial valves and fittings. Copper nickels, aluminum bronzes, silicon bronzes, manganese bronzes, and tin and phosphor bronzes should be considered for such environments. 
 
 
Keywords: 
 
copper alloys; 
marine alloys; 
Unified Numbering System (UNS)

Konrad J. A. Kundig

Papers

4 Copper and Copper Alloys

Copper and Copper Alloys