Making Single-Crystal Fibers in a Laser-Heated Floating Zone

Figure 1 shows an apparatus for growing a single-crystal fiber by solidification from a floating zone of laser-heated molten material on the tip of a feed rod. The apparatus can be used to produce single-crystal fibers of various highly pure ceramic and metal compositions, controlled crystal orientations, and small, uniform diameters. Such fibers are needed for experimental research on fiber reinforcements for metal-matrix/fiber and intermetallic-matrix/fiber composite materials. Fiber compositions that have been produced thus far include sapphire (Al2O3) with and without ternary additions, ZrO2, and yttrium aluminum garnet (YAG). Typical fiber diameters have ranged from 100 to 250 µm.