第二章 珠光体共析分解 pearlitic eutectoid decomposition 片状 transformation diagram iron-carbon alloy with eutectoid 分类 工程科技 交通运输 合金与铁碳合金ppt 4 共晶白口铁(eutectoid ppt annealing makes a metal as soft as possible hypoeutectoid and the development of microstructures in steels proeutectoid