grain contrast

• 晶粒对比

grain contrast的用法和样例：

例句

1. Austenite grain size of plain carbon steel and alloy steel were examined by oxidization and grain boundary etching method.
   采用氧化法和晶粒边界腐蚀法对几种不同的碳钢和合金钢的奥氏体晶粒的显示进行了对比试验。