0Cr18Ni9不锈钢表面纳米化及其热稳定性研究

对0Cr18Ni9不锈钢进行表面超音速微粒轰击处理,使表面获得纳米晶粒,并且晶粒尺寸沿厚度方向逐渐增大呈梯度组织。将处理后的样品进行不同加热温度和保温时间的热处理,研究其组织结构和硬度的变化。结果表明:当加热温度低于500℃时,表层晶粒尺寸未发生明显变化,只是在表面纳米晶层及其相邻的亚微晶层上发生马氏体相变,对应的硬度沿深度分布也未见明显的改变;当加热温度高于500℃时,表层组织发生回复与再结晶,导致硬度明显下降。与加热温度相比,保温时间对组织和硬度的影响不大。

Study on Surface Nano-crystallization of 0Cr18Ni9 Stainless Steel and Its Thermal Stability

After supersonic fine particles bombarding (SFPB) for 0Cr18Ni9 austenite stainless steel, a gradient microstructure on the surface of the layer with grain size from nano-scale to micro-scale was obtained. Then, the annealing treatment for the SFPB sample at different temperature and holding time was carried out. The microstructure and the hardness of the SFPB sample before and after annealing were analyzed. Experimental results show that, when the annealing temperature is lower than 500 ℃, the grain size on the surface of microstructure hasn't obviously change, except the martensite transformation in the affected layer, and the hardness distribution along the depth remains unchanged.When the heating temperature is higher than 500 ℃, recovery and recrystallization occur in the gradient microstructure, which induces significant reduction of the hardness along the depth. The effect of holding time on the microstructure and properties of the SFPB sample is less important compared with the beating temperature.