This paper reviews the status of technology in design and manufacture of new wrought polycrystalline Ni-base superalloys for critical engineering applications. There is a strong motivation to develop new alloys that are capable of operating at higher temperatures to realize improvements in thermal efficiency, which are necessary to achieve environmental targets for reduced emissions of harmful green-house gases. From the aerospace sector, the development of new powder metallurgy and ingot metallurgy alloys is discussed for disk rotor and static applications. New compositions for powder metallurgy contain about 50 to 55 pct of gamma prime (γ′) strengthening precipitates to ensure components operate successfully at temperatures up to 788 °C (1450 °F). In contrast, new compositions for ingot metallurgy aim to occupy a design space in temperature capability between Alloy 718 and current powder alloys that are in-service, and show levels of γ′ of about 30 to 44 pct. The focus in developing these alloys was design for manufacturability. To complement the aerospace developments, a review of work to understand the suitability of candidate alloys for multiple applications in Advanced-Ultra Supercritical (AUSC) power plants has been undertaken by Detrois, Jablonski, and Hawk from the National Energy Technology Laboratory. In these power plants, steam temperatures are required to reach 700 °C to 760 °C. The common thread is to develop alloys that demonstrate a combination of high-temperature properties, which are reliant on both the alloy composition and microstructure and can be produced readily at the right price. For the AUSC applications, the emphasis is on high-temperature strength, long-term creep life, phase stability, oxidation resistance, and robust welding for fabrications. Whereas for powder disk rotors in aircraft engines, the priority is enhanced resistance to time-dependent crack growth, phase stability, and resistance to environmental damage, while extending the current strength levels, which are shown by existing alloys, to higher temperatures.

本文回顾了用于关键工程应用的新型锻造多晶镍基高温合金的设计和制造技术的现状。有强烈的动机去开发能够在更高温度下工作以提高热效率的新合金，这对于实现减少有害温室气体排放的环境目标是必不可少的。在航空航天领域，讨论了用于磁盘转子和静态应用的新型粉末冶金和锭冶金合金的开发。粉末冶金的新成分包含约50至55 pct的γ′（γ'）增强沉淀物以确保组件在高达788°C（1450°F）的温度下成功运行。相比之下，用于铸锭冶金的新成分的目的是在合金718和当前使用的粉末合金之间占据一定的温度能力设计空间，并显示出γ含量'大约30到44 pct。开发这些合金的重点是可制造性设计。为了补充航空航天的发展，国家能源技术实验室的Detrois，Jablonski和Hawk进行了一项工作回顾，以了解候选合金在先进超超临界（AUSC）发电厂中的多种应用的适用性。在这些发电厂中，蒸汽温度需要达到700°C至760°C。共同的任务是开发出具有高温特性的合金，这些合金既依赖于合金的成分，又依赖于微观结构，并且可以以合适的价格容易地生产。对于AUSC应用，重点是高温强度，长期蠕变寿命，相稳定性，抗氧化性以及用于制造的坚固焊接。