Beginning one million years ago, early humans utilized stones as tools-an era known as the Paleolithic Age. By 10,000 years ago, humans had begun to refine stone implements, fashioning them into vessels and sophisticated tools, thereby ushering in the Neolithic Age. Archaeological excavations demonstrate that, in my country, practical pottery was being produced over 8,000 years ago; brass was being smelted over 6,000 years ago; simple bronze tools were in use over 4,000 years ago; and weapons forged from meteoric iron were being manufactured over 3,000 years ago. Furthermore, during the Spring and Autumn Period-over 2,500 years ago-our ancestors had already mastered the smelting of cast iron, a feat achieved more than 1,800 years earlier than in Europe.
In the mid-19th century, the advent of modern open-hearth and converter steelmaking technologies marked humanity's true entry into the Iron and Steel Age. Concurrently, copper, lead, and zinc came into widespread use, while metals such as aluminum, magnesium, and titanium subsequently emerged and found practical application. Throughout the history of the materials industry, metallic materials have consistently occupied a dominant position. Indeed, metallic materials can be described as witnesses to the entire trajectory of human societal development-a distinction inextricably linked to the pivotal roles they have played during every transitional phase of human history. As one of the very first materials discovered and utilized by humanity, metals have, in virtually every respect, shaped the course of human historical development. From the earliest instances of forging metals into hunting weapons to our present-day existence-which is utterly inseparable from metals-it is evident that metals have long been deeply integrated into the fabric of human society. This begs the question: what roles have metals played in the past of human society, and what roles will they play in its future?
In the context of human history, the role played by metals has often served as a microcosm reflecting the very nature of a specific era-such as the Neolithic Age, the Bronze Age, and so forth. Fundamentally, the primary reason these eras are designated as such lies in the fact that, during each respective period, humans discovered and developed a specific new metal-a metal that, in turn, largely determined the trajectory of human civilizational development during that time.
