Growth of Nickel-Base Superalloy Single Crystals

9322353郭镍基高温合金是我们的航空航天工业和我们的能源工业的一些领域的关键材料。镍基高温合金单晶在高温燃气轮机中表现出优异的性能。这笔赠款支持大学和产业界合作，通过从液态熔体中拉出的方法生长镍基高温合金的成形单晶。单晶在威斯康星大学生长，并在Howmet Corporation进行测试，Howmet Corporation是美国高温燃气轮机用镍基高温合金单晶的主要生产商。其目标是证明生长低成本、高质量的等截面单晶(棒材、棒材、薄片和管材)的可行性。这些晶体适用于不需要复杂形状的应用，例如涡轮发动机燃烧室衬里的单晶片(气体混合物被点燃)。一个优点是，不需要涉及陶瓷外壳模具的准备和移除的许多步骤，并且晶体不限于相对较短的长度，不像传统的通过熔模铸造的镍基高温合金的晶体生长。人们的注意力集中在生长长达2英尺的单晶片上。使用了威斯康星大学晶体生长实验室最近开发的一种改进的拉形晶体技术，并由Howmet对单晶进行了热处理和初步筛选试验。将制作一部展示拟议工作结果的录像带电影，并向高温合金行业分发副本。它还将用于威斯康星大学的两门本科生材料处理课程。***

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. ***