原位TiC颗粒弥散强化304不锈钢的制备及组织性能研究

STUDY ON FABRICATION,MICROSTRUCTURE AND PROPERTIES OF IN SITU TiC PARTICLE ON DISPERSION-STRENGTHENED 304 STAINLESS STEEL

用原位熔铸法制备了TiC颗粒弥散强化304不锈钢.显微组织观察表明,原位合成的TiC颗粒尺寸在3—10μm之间,局部有轻微团聚现象.TiC颗粒的加入,使304不锈钢的强度明显提高,但塑性有所下降;TiC弥散强化304不锈钢铸锭经电渣重熔后,TiC颗粒细化,分布更均匀,且在显微组织中可观察到纳米尺度的TiC颗粒.电渣重熔后强化钢的强度进一步提高,塑性也有所改善.在650℃/150 MPa的条件下,引入TiC颗粒的强化钢抗蠕变性能远高于304母合金,而电渣重熔后,由于TiC颗粒的细化,钢的抗蠕变性能进一步改善.

TiC dispersion-strengthened 304 stainless steel was fabricated using the technique of in situ reaction during melting of the steel.Microstructure observation reveals that the distribution of the added TiC particles with the size of 3—10μm is basically uniform in the matrix grains,but slight aggregation of particles is observed in a few areas in the microstructure.The addition of TiC particles into 304 stainless steel results in the increase of ultimate strength,but the decrease of ductility.When the ingot of the TiC dispersion strengthened 304 stainless steel prepared is remelted by the technique of electroslag remelting,TiC particles in the steel are significantly refined and the distribution of them becomes more homogeneous,therefore the tensile properties of the steel are further improved in comparison with that before electroslag remelting.Some tiny TiC particles with nano-scale were observed in the microstructure of the steel after electroslag remelting.Introduction of TiC particles to 304 stainless steel also causes a notable increase in creep resistance at the temperature of 650℃and applied stress of 150 MPa and the further improvement on creep properties of the steel is obtained after electroslag remelting.