The zinc coating layer fracture properties of a galvannealed steel and an electrolytically galvanized steel are analyzed by conducting the in-situ bending test with newly designed samples. It is found that the fracture develops much earlier in the coating layers of the galvannealed steel than that of the electrolytically galvanized steel. Using transmission electron microscope and energy dispersive X-ray spectroscopy, the intermetallic phases of the coating layers are characterized and it is found that the early crack initiation in a galvannealed steel is mainly triggered in the gamma phase. Combining with nanoindentation tests and corresponding simulation, the deformability of intermetallic phases are analyzed to explain the failure behavior of coating layers in the two steels.

通过对新设计的样品进行原位弯曲试验，分析了镀锌钢和电解镀锌钢的锌涂层断裂性能。已经发现，与电镀锌钢相比，镀锌钢涂层中的裂纹发展得早得多。使用透射电子显微镜和能量色散X射线光谱法，表征了涂层的金属间相，并且发现镀锌退火钢中的早期裂纹萌生主要是在γ相中引发的。结合纳米压痕试验和相应的模拟，分析了金属间相的可变形性，以解释两种钢中涂层的破坏行为。