iron aggregate

例句：

1. 1. The construction of the new bridge required the use of iron aggregate.
   建造新桥需要使用铁合金。
2. 2.The engineers used iron aggregate to strengthen the structure.
   工程师们使用铁合金来加固结构。
3. 3. The aggregation of different materials into one composite material is known as an alloy.
   将不同材料聚合成一种复合材料被称为合金。