Bronze alloying recipes of Yue state: new evidence from bronze artifacts and metal ingots unearthed at the Dahutou site in Shaoxing, Zhejiang, China

Abstract

Yue state was one of the most significant vassal states during the Eastern Zhou Dynasty, and Shaoxing, Zhejiang Province as the capital of the Yue state was discovered the Dahutou site, which has been excavated on a large scale in recent years, and has constituted a significant archaeological discovery pertaining to the Yue state. The Dahutou site has yielded a substantial quantity of bronze artifacts with distinctive Yue cultural characteristics, and notably, it marks the first concentrated discovery of lead and tin metal ingots through the scientific excavation. In this paper, a total of 95 samples of bronzes and metal ingots unearthed at the Dahutou site were analyzed by technological analyses, including metallographic microscope, scanning electron microscope, and ED-XRF. The results reveal that bronze artifacts from the Dahutou site were primarily produced through casting and predominantly consisted of copper-tin–lead ternary alloys, characterized by a high tin content. Additionally, evidence of tin-plating and carving techniques has also been uncovered. While a small portion of the metal ingots comprised lead ingots and tin ingots, the majority were lead–tin alloy ingots, which exhibited two formulations: high-lead low-tin and high-tin low-lead, revealing that the ternary alloy bronzes in the Eastern Zhou period were not directly made by fusing the pure metal ingots of copper, tin, and lead together. Instead, it is likely that the predominant alloying technique at the time involved blending two types of alloy ingots. The newfound discoveries at the Dahutou site provide crucial insights for exploring bronze alloy technology during the Eastern Zhou period.