原位TiC颗粒增强Fe-36Ni因瓦合金的组织与性能

在经典Fe-36Ni因瓦合金熔池中添加微量Ti元素,原位生成TiC。与传统因瓦合金相比,所得因瓦合金屈服强度和抗拉强度分别提高约10%,同时塑性和膨胀性能良好。透射电镜观察到合金中分布有几十到几百纳米的细小颗粒,这些颗粒形状近似球形或椭球形,与周围基体结合良好,根据相机常数与晶面间距之间的关系,判定其为TiC。TiC的吉布斯标准生成自由能较Ni3Ti更低。TiC强化因瓦合金的主要方式为Orowan强化。

Microstructure and Properties of Fe-36Ni Invar Alloy Reinforced by In Situ TiC Particulates

After adding a small amount of Ti into the molten Fe-36Ni Invar alloy, TiC particulates formed in-situ. The yielding strength and the ultimate strength of the strengthened Invar alloy with a small amount of Ti rise about 10% individually compared with the Invar alloy without any alloying element, and both the ductility and the thermal expansion coefficient remain about the same. Particulates ranging from tens of nanometers to hundreds of nanome- ters were observed by the transmission electronic microscope. These particulates have spherical or ellipsoidal shapes, and combine well with the matrix. According to the relationship between the camera constant and the inter- planar spacing, these particulates are determined to be TiC. The standard free energy of formation of TiC is lower than which of Ni3 Ti. The Orowan strengthen is considered to be the main strengthen mechanism.