摘要: An Egyptian metal vase from the Ptolemaic period was investigated metallurgicallyand fractographically. The metal is nearly pure silver, and chemical analysis indicates it was obtained from the cupellation of lead. Despite its hig... 展开 An Egyptian metal vase from the Ptolemaic period was investigated metallurgicallyand fractographically. The metal is nearly pure silver, and chemical analysis indicates it was obtained from the cupellation of lead. Despite its high purity (in archaeological terms) the metal is severely cracked and embrittled, with fractures mainly along grain boundaries. Factors contributing to this damage are work-hardening and residual deformation in the microstructure (slip and twinning), corrosion along slip lines and twin boundaries, corrosion in band that are the remains of coring (solute element segregation during solidification), large equiaxed grains, externally applied forces and internal residual stresses. The metal is now easily broken into small pieces, i.e. it is friable. This must be taken into account during any further restoration of the vase. A procedure to better preserve the vase is suggested. 收起