摘要
通过OM、SEM和XRD对触变成形并经5年自然时效的铸态ZA27合金的微观组织进行了观察。结果表明:经触变成形后的ZA27合金由近球状初生粒子α′相和晶间的二次凝固组织组成。其中α′相主要有两种形态:一是颗粒内部存在"小液池";二是颗粒内部比较均匀,不存在二次凝固组织。晶间的二次凝固组织也以两种形态存在:一是在共晶边缘处形成体积不均的"孔洞"或是"孔洞"串在一起形成的"沟";二是在共晶内部已经分解为层片组织的大"孔洞"。共晶方式主要为离异共晶及其中"蜂窝"状棒状共晶,部分区域出现不规则层片共晶。
The microstructure of thixoformed ZA27 was examined by optical microscope,scanning electron microscope and X-ray diffraction after ageing for 5 years at ambient temperatures.It is found that the microstructure is composed of aluminum-rich α′ dendrites and eutectic structure in the interdendritic region.The α′ phase has two patterns.One contains liquid pools while the other does not contain secondary solidification in the particles.The secondary solidification phase also has two forms in the crystals.One has holes of different sizes or ditches formed by connected holes while the other contains big holes formed of decomposed lamellae in the eutectic structure.The eutectic modes are mainly separated eutectic structures and rod-like eutectic structure shaped like honeycombs.In some regions the eutectic structure appears as irregular lamellae.
出处
《上海有色金属》
CAS
2010年第3期106-110,共5页
Shanghai Nonferrous Metals
