长时间水浸泡奥贝球铁的腐蚀行为及拉伸性能

研究了长时间水浸泡奥贝球铁(ADI)的腐蚀行 为和拉伸性能.浸泡中，ADI的石墨周围的基体被腐蚀，形成腐蚀凹坑；其中的针状铁素体优 先腐蚀.水附着拉伸试验中，浸泡后试样的抗拉强度和延伸率比未浸泡的低，发生明显的水 脆化.干燥使浸泡后试样的强度和延伸率恢复到较高水平，但腐蚀凹坑和表面腐蚀溶解减少 了试样的有效断面积，其抗拉强度和延伸率低于大气中的.与浸泡在离子交换水相比，自来 水加速试样腐蚀，其水脆化程度也明显.

CORROSION BEHAVIOR AND TENSILE PROPERTIES OF AUSTEMPERED DUCTILE IRON AFTER LONG TIME IMMERSION IN WATER

The corrosion behavior and tensile properties of austempered ductile iron(ADI) immersed in water for a long time was investigated from the viewpoints of corrosion and water embrittlement.Matrix adjacent to graphite nodule was eroded away and corrosion pit formed when ADI was immersed in water for a long time.And acicular ferrite in matrix was corroded preferentially.The tensile strength and elongation of ADI tested under the wet condition after immersion in water for 480h,were lower than non-immersed specimen,i.e.the drastic water embrittlement was observed.When specimens were immersed in the tap water for a long time,the tensile strength and elongation were recovered to a certain degree after drying.The tensile properties of specimen dried after immersion were not completely recovered to the level tested in air because of reduction of cross sectional area due to the corrosion pits and surface dissolution.When the specimens were immersed in tap water for a long time,the water embrittlement was more remarkable than the specimen immersed in ion exchange water.This is because of the corrosion of specimen was promoted by tap water.