核设备端帽用Zr-4合金棒材,过去常出现“疏松”或“白芯”现象,严重影响着出口任务的完成。为了弄清原因,提出改进办法。上海有色金属研究所的研究人员借助于金相、扫描电镜、电子探针等手段对各种不同生产工艺的样品作了仔细的观察。结果认为,这种“疏松”是基于Zr(FeCr)_2相的不均匀性分布及其严重酸蚀情况下的受蚀所致。采用高温长时间扩散热处理(淬火退火)虽可改善其分布,但不宜于大生产。由于Zr(FeCr)_2相可以强化基体,阻止晶粒长大,在中性介质中不受腐蚀,因此可尽量采用合理的最大 Zr-4 alloy bar for nuclear equipment end caps used to be “loose” or “white core” in the past, which seriously affected the completion of export tasks. In order to clarify the reasons, put forward improvements. Shanghai Institute of Nonferrous Metal researchers with the help of metallographic, scanning electron microscopy, electronic probes and other means of a variety of different production process samples were carefully observed. The results show that this “looseness” is based on the inhomogeneous distribution of the Zr (FeCr) 2 phase and the corrosion under severe acid corrosion. The use of long-term high-temperature diffusion heat treatment (quenching and annealing) Although the distribution can be improved, but not suitable for large-scale production. Because Zr (FeCr) _2 phase can strengthen the matrix to prevent the grain growth, in the neutral medium from corrosion, so try to use a reasonable maximum