grained layer

例句：

1. 1. The engineer used a laser to create a grained layer on the surface of the metal.
   工程师使用激光在金属表面创建了一个粒状层。
2. 2. The grained layer helps to reduce friction between the moving parts.
   粒状层有助于减少移动部件之间的摩擦。
3. 3. The grained layer is responsible for the material's strength and durability.
   粒状层负责材料的强度和耐用性。