张掖西城驿遗址出土铜器的初步研究

Preliminary Study on the Bronzes from the Xichengyi site in Zhangye

甘肃张掖西城驿遗址出土金属遗物42件,包括工具、饰品等器物34件,铜块8件,年代为距今4000年至3600年。经SEM-EDS和金相检测分析,25件红铜,10件Cu-As,1件Cu-Sb,2件Cu-Sn,2件Cu-As-Sb,2件为白冰铜器物或铜块;在可明确观察组织的32件器物中,铸造13件,1件铸造后冷锻,8件热锻,10件热锻后冷锻。34件器物中铜锥20件,占58.9%,其中7件铸造,5件热锻,7件热锻后冷锻,1件铸造后冷锻。在合金种类、器物类型、加工技术上没有明确的对应关系。As、Bi、Sb、Pb、Ag(以金属或矿物形式存在)和Sn(以Sn O2形式存在)在大量红铜器物中存在的形态表明,古代工匠已尝试获取合金,但是由于还原气氛低下而难以获得。所有的检测表明,西城驿遗址的冶金已进入从红铜—砷铜合金到锡青铜的青铜时代早期阶段。

A total of 42 metal items have been unearthed from the Xichengyi site in Zhangye, Gansu Province, dating back from 4000 BP to 3600 BP. This assemblage includes 34 artifacts such as tools and ornaments and 8 ingots. SEM- EDS and metallographic examination shows that these samples include 25 red copper, 10 Cu-As alloys, 1 Cu-Sb alloys, 2 Cu-Sn alloys, 2 Cu-AsSb alloys, and 2 white matte artifacts or ingots. Among the 32 artifacts with identifiable microstructure, 13 were made by casting,1 was made by casting and cold forging, 8 were made by hot forging, and 10 were made by hot and cold forging. Among the 20 items of awls, which represent 58.9% of all 34 artifacts, 7 were made by casting, 5 were made by hot forging, 7 were made by hot and cold forging, and 1 was made by casting and cold forging. There were no clear correlations between the alloy styles, artifacts types, and manufacturing techniques. As, Bi, Sb, Pb, Ag（in the form of metal or oxides）, and Sn（in the form of Sn O2） were found in most of the copper artifacts, indicating that ancient craftsman had attempted to obtain alloys but had encountered a technical a difficulty in achieving the right results in the weak reducing atmosphere. All the tests above indicate that the metallurgy at the Xichengyi site had reached the early phase of the Bronze Age from using copper-arsenic alloy to tin bronze.