Archaeometallurgy: Metallographic Evidence of Ur-period Gold Hammering
冶金考古：乌尔王朝金片锤揲的金相证据
标签：冶金考古, 金相, 乌尔, 锤揲
大英博物馆对乌尔王室墓（约公元前 2550 年）金饰的取样金相显示：0.2–0.4 mm 金片晶粒沿锤打方向拉长并布满滑移带，随后经历 600–650 ℃ 短时退火形成孪晶等轴晶，证明"锤揲—退火"循环至少 5–7 次；从晶粒尺寸的空间分布可反推断续换砳与局部退火的顺序。这种"可读的锤序"如今用于真伪鉴别——现代冷轧带材仿品晶粒均匀，缺少逐段退火留下的不均匀特征，据此可甄别流入市场的古代金器赝品。
Metallographic samples from the Royal Cemetery of Ur ornaments (c. 2550 BC, British Museum) show grains in 0.2–0.4 mm gold elongated along the hammering direction and laced with slip bands, followed by short 600–650 °C anneals producing twinned equiaxed grains—proof of at least 5–7 hammer-and-anneal cycles. The spatial pattern of grain sizes even reconstructs the order of re-blocking and local anneals. This "readable hammer sequence" now serves authentication: modern rolled-strip fakes show uniform grains lacking the patchy signatures of piece-by-piece annealing.