On Extremity Trends in Advances of Materials

Abstract

The science & technology of materials has grown phenomenally during the last five decades. This article is an attempt at an overview of not so much the myriad individual materials that have been made and used but of a more general nature in which we seek to understand the developments in the material—process—property system. We point out that resorting to extremities in each of these aspects is one discernible trend. Making materials with more than three or four components, using extremities in process temperature & pressure and having to evaluate material properties at very high strain rates are an illustration of the extremity trends apart from the now famous extremities in chemical state, namely, nano sizes and amorphousity. What emerges is that there is colossal room in these extreme situations for fundamental data generation, e.g., thermochemical and diffusion related parameters, and understanding of the underlying mechanisms so essential for developing predictive capability with respect to material behaviour.

Keywords:

• Multi-component materials
• high temperature—high pressure
• high fields
• process space
• thermochemistry
• phase equilibria
• diffusion
• mechanical behaviour
• complex stress state
• high strain rate deformation
• systems approach
• materials design

Acknowledgement

This paper is in expression of the authors sincere gratitude and respectful admiration for Prof EC Subbarao (ECS). One of us (KB) was an undergraduate student and was taught by him at the Indian Institute of Technology, Kanpur, India. The other author (PRR) has been a life long associate, learning and receiving inspiration from Prof ECS, ever since he came into contact with him at the beginning of his professional career in the 1960s. Prof ECS was the first among the founding fathers of materials science education in India and has remained a leading light and a source of inspiration to generations of students and researchers. The authors feel deeply beholden to him for his wholehearted encouragement and unbounded kindness.

PRR would also like to thank the Indian Space Research Organization for the award of a Professorship.