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模拟热镀锌工艺,在实验室生产了1000MPa级热镀锌双相钢.利用原位拉伸实验,对其断裂行为进行了观察,进一步探讨了其断裂机理.结果表明:实验用钢经820℃退火后,可以获得抗拉强度为1022MPa、延伸率为9.5%的F+M双相钢;动态拉伸过程中,裂纹尖端的塑性区会萌生新的微裂纹,塑性区内的铁素体晶粒内部会产生“波状”滑移带;当裂纹扩展到马氏体岛时会改变方向绕过马氏体,扩展到铁素体晶粒时,以微孔相连的塑性方式使铁素体开裂;最终断裂以塑性断裂的形式发生,断口形貌为韧窝状.
Simulated hot-dip galvanizing process, 1000MPa hot-dip galvanized duplex steel was produced in the laboratory.The fracture behavior was observed by in-situ tensile test and the fracture mechanism was further explored.The results show that the experimental steel 820 After annealing, the F + M dual phase steel with the tensile strength of 1022MPa and the elongation of 9.5% can be obtained. During the dynamic tensile process, the new microcracks will be induced in the plastic zone at the crack tip. The ferrite When the crack propagates to the martensite island, it will change its direction and bypass the martensite. When it expands to the ferrite grain, the iron Element body cracking; the final fracture in the form of plastic fracture occurs, the fracture morphology is dimpled.