Texture Formation in Thin Tapes from Ni-Based Ternary Alloys with Cr, W, Mo and V

Texture, structure, and magnetic and mechanical properties of thin tape substrates fabricated of ternary nickel alloys with chromium, tungsten, molybdenum, and vanadium have been investigated. It has been shown that in Ni93.8Cr4.0Mo2.2, Ni88.5Cr6.2V5.3and Ni88.4Cr9.2W2.4 alloys a sharp cube texture can form, which is stable up to high annealing temperatures. In the Ni87.6Cr8.0Mo4.4alloy, other weak orientations are present, along with the strong cube component. The possibility of obtaining a sharp cube texture after primary recrystallization is controlled by the quantitative relationship between the texture components in a cold-rolled tape, which is determined by the method of orientation-distribution functions. Three alloys studied are non-magnetic at 77 K.

Effect of Ultrahigh Straining on the Evolution of Cube Texture ({100}<100>) in High Purity Nickel

The effect of ultrahigh straining on the evolution of cube texture in high purity nickel (99.97%) processed by Accumulative Roll Bonding (ARB) is investigated in the present study. Fully recrystallized nickel sheet having average grain size of 28 μm is deformed by ARB to the strain levels of εeq=3.2 and εeq=6.4 corresponding to 4 and 8 cycles of ARB processing, respectively, and subsequently annealed at different temperatures. The 8 cycle ARB processed material consistently shows much higher cube volume fraction as compared to the 4 cycle processed material after different annealing treatments. Almost 100% cube volume could be obtained in the 8 cycle processed material after annealing at 800°C. The development of extremely sharp cube texture in the 8 cycle processed material could be attributed to the oriented nucleation of cube grains at early stages of recrystallization and subsequent growth of these grains. The results indicate that ultrahigh straining could be useful for applications requiring near perfect cube texture such as substrates for coated superconductors applications.

Investigation Texture in Ni-W Alloy Substrates for Coated Conductors

It is well know that Ni-5at.% W(Ni5W) and Ni-9.3at.% W(Ni9W) alloy substrates are two kinds of promising materials to be employed in coated conductors. The Ni5W substrate is very easy to produce cube texture, while the Ni9W alloy has a lower magnetic property and higher strength. However, the pure cube texture are not capable to be obtained in Ni9W alloy. In this work, the preparation and texture development in both Ni5W and Ni9W alloy substrates have been reported. Highly biaxial textured Ni5W substrate was fabricated by cold rolling, followed by three different annealing routes. The texture analysis indicated that a sharp cube texture was formed after annealing at a wide temperature range of 800-1100°C in as rolled Ni5W substrate. The high quality of cube orientation was obtained after a two step annealing (TSA) with farthing twin boundaries analyzed by EBSD. Furthermore, in order to obtain a pure cube texture in Ni9W alloy substrate, a typical rolling process was performed and the deformation texture was optimized in these substrates. The designed deformation texture components were obtained in Ni9W alloy when pre-heating the ingot at 250 °C before performing a cold rolling, which shows a possibility to form cube texture in Ni9W alloy substrate after annealing.

Cube Texture Formation in P/M Ni, Ni-W and Ni-Mo Alloy Tapes for Coated Superconductor Applications

Pure Ni, Ni-5at.%Mo and Ni-5at.%W prepared through P/M route have been severely cold deformed (~95%) and given different heat treatments to develop sharp cube component ({001}<100>) for coated superconductor applications. It was found that amongst the three materials studied, Ni-5at%W develops the most sharp cube texture. This is in contrary to the observation in similar materials produced by the melting and casting route.