Growth of Nickel-Base Superalloy Single Crystals

小行星9322353 镍基高温合金是航空航天工业和能源工业某些领域的关键材料。 单晶镍基高温合金在高温燃气轮机中表现出优异的性能。 该补助金支持大学与工业界合作，发展成形的单一 镍基高温合金的晶体从液态熔体中拉出。 单晶在威斯康星州大学生长，并在Howmet Corporation进行测试，Howmet Corporation是美国高温燃气涡轮机用镍基高温合金单晶的主要生产商，其目标是证明生长的可行性低成本、高质量的恒定横截面单晶（棒、条、板和管）。 这些晶体可用于不需要复杂形状的应用，例如， 用于涡轮机发动机燃烧室衬套（气体混合物在此点燃）的单晶片。 一个优点是不需要在陶瓷壳模的制备和移除中涉及的许多步骤，并且晶体不限于相对短的长度，这与通过熔模铸造的镍基超合金的常规晶体生长不同。 注意力集中在长达2英尺的单晶片的生长上。 最近在威斯康星州大学的晶体生长实验室开发了一种改进的拉晶技术，并由Howmet进行了单晶的热处理和初步筛选试验。 将制作一部录像带，展示拟议工作的结果，并将副本分发给高温合金行业。 它还将用于威斯康星州大学的两门本科材料加工课程。 ***

9322353 Kuo Nickel-base superalloys are critical materials to our aerospace industry and to some areas of our energy industry. Single crystals of nickel-base superalloys have demonstrated excellent performance in high-temperature gas turbines. This grant supports a university-industry collaboration on the growth of shaped single crystals of nickel-base superalloys by pulling from liquid melts. Single crystals are grown at the University of Wisconsin and tested at Howmet Corporation, a major producer of single crystals of nickel-base superalloys for high-temperature gas turbines in the U.S. The objective is to demonstrate the feasibility of growing low-cost, high-quality single crystals of constant cross-sections (rods, bars, sheets and tubes). These crystals are useful for applications where complicated shapes are not required, e.g., single crystal sheets for turbine engine combustor liners (where gas mixtures ignite). An advantage is that numerous steps involved in the preparation and removal of ceramic shell molds are not required and the crystals are not limited to relatively short lengths, unlike conventional crystal growth of nickel-base superalloys by investment casting. Attention is focused on growth of single crystal sheets up to 2 feet long. An improved technique for pulling shaped crystals, recently developed at the University of Wisconsin's crystal growth laboratory, is used and heat treating and preliminary screening tests of the single crystals are conducted by Howmet. %%% A videotape movie showing the results of the proposed work will be made and copies distributed to the superalloy industry. It will also be used in two undergraduate materials processing courses at the University of Wisconsin. ***