Material Behavior and Performance in Environments of Extreme Pressure and Temperatures

Abstract

The aim of this article is to review the mechanical behavior and performance of the metallic materials under extreme pressure and temperature. Materials are central to every technology, and future technologies in all fields will place increasing demands on materials performance with respect to extremes including temperature and pressure. For example, today’s state-of-the-art industrial gas turbines (IGT) working at about 50–60% efficiency with a temperature about 1500°C. Increasing this efficiency to above 60% requires raising operating temperatures and essentially the operating pressures. These increasingly extreme operating environments accelerate the aging process in materials, leading to reduced performance and eventually to failure. Therefore developments of new materials that can reliably withstand these extreme thermal and pressure environments are demanding. If one extreme condition is harmful, two or more can be devastating. Currently, researchers are confident that today’s gaps in materials performance under extreme conditions could be bridged if the physical and mechanical changes that occur in bulk materials and at the interface with the extreme environment could be understood. These complex and interrelated changes can be unraveled as advances are realized in characterization and computational tools. In this regard, this article will discuss the technologies and materials used in extreme pressure and temperature environments taking the modern IGT as a case study. However, it was found necessary before reviewing the material development of this gas turbine case study, is to provide a review of the principles of the high temperature and pressure mechanical properties. Among those it was found that the creep, fatigue (high-cycle fatigue (HCF), low-cycle fatigue (LCF), and thermomechanical fatigue (TMF)), and creep–fatigue interaction are the most significant properties, which was reviewed in more details. The evolution of the gas turbine has been made possible through the deployment of advanced materials and technologies. The background of these advancements, their use in the gas turbine, and the drivers for new technologies to achieve higher temperatures and efficiencies was the main focus.