Individual carbon nanotubes are like minute bits of string, and many trillions of these invisible strings must be assembled to make useful macroscopic articles. We demonstrated such assembly at rates above 7 meters per minute by cooperatively rotating carbon nanotubes in vertically oriented nanotube arrays (forests) and made 5-centimeter-wide, meter-long transparent sheets. These self-supporting nanotube sheets are initially formed as a highly anisotropic electronically conducting aerogel that can be densified into strong sheets that are as thin as 50 nanometers. The measured gravimetric strength of orthogonally oriented sheet arrays exceeds that of sheets of high-strength steel. These nanotube sheets have been used in laboratory demonstrations for the microwave bonding of plastics and for making transparent, highly elastomeric electrodes; planar sources of polarized broad-band radiation; conducting appliqués; and flexible organic light-emitting diodes.

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800MPa grade Advanced High Strength Steels (AHSS), Complex Phase steel CP800, containing microalloying elements, are chosen to test the stamping properties in different test conditions and compared with traditional high strength low alloy (HSLA) steels HSLA S700MC. Tensile test, and HAT shape stamping test are taken to investigate the properties of the materials. Test results indicate that the studied 800MPa grade AHSS shows a better strength ductility balance compared with the reference HSLA steels. Under the same HAT shape springback stamping condition, HSLA steels S700MC always show the largest springback deformation among the investigated steels. While springback angles of all the AHSS studied are markedly smaller than that of steel S700MC. Among the 3 kinds of AHSS researched, CP800T always show the largest springback deformation. Domestic steel CP800 and imported CP800S show much smaller springback deformation respectively. In BHF of 100KN condition, springback deformation of 3 kinds of AHSS reaches the top value among all the BHF conditions. However, steel CP800 indicates an outstanding springback restrain trend in blank holding force (BHF) further increasing attempt. Thus, springback behavior can be restricted obviously by using a larger blank holding force (BHF) in steel CP800 stamping cases.

High‐N Mn18Cr18 alloy is mainly used as drill collar (DC) and retaining rings due to its non‐magnetism and outstanding corrosion resistance. This work focuses on studying the dynamic recrystallization (DRX) behavior and thermal mechanical properties of high‐N Mn18Cr18 alloy through isothermal single‐pass compression tests on Gleeble‐3500 simulator at the temperatures from 900–1200 °C and strain rates from 0.001–1 s−1. Flow stress curves combined with metallographic analysis indicate that DRX tends to occur at high deformation temperatures and low strain rates. The deformation activation energy of high‐N Mn18Cr18 alloy is 331.775 kJ mol−1. Besides, fifth order polynomial fitting for determining critical strain and nonlinear curve fitting for extrapolating work hardening stress are presented. Based on kinetics equations of DRX and the dislocation density model, constitutive model is been set up to predict the flow stress behavior. Comparisons between the experimental and the predicted flow stress values indicate good forecast precision of the established model.

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