NiTi短纤维对Ti(C,N)基金属陶瓷组织和性能的影响

本文研究了添加直径为0.08mm、长度为2mm、添加量0～16wt%、等原子比的NiTi合金短纤维对Ti(C,N)基金属陶瓷组织和性能的影响,试样采用粉末冶金的方法制备,采用OM、XRD、SEM等对其进行分析。结果表明,压制成型时,随着NiTi短纤维加入量的增加,原料的流动性逐渐变差,导致压成的素坯的致密度降低;在烧结过程中,由于大部分Ni形成Ni-Co固溶体或被蒸发,因此大部分NiTi合金的原子比被破坏,烧结时液态的NiTi会填充试样内部的空隙,由于素坯的致密度较低,液相不能完全填充,导致在冷却后金属陶瓷中出现了许多孔洞,且随着NiTi合金短纤维加入量的增加,金属陶瓷的孔洞逐渐增加,其致密度和抗弯强度也随着下降。

Effects of NiTi Short Fiber on the Microstructure and Properties of Ti(C,N)-based Cermet

The effects of equiatomic NiTi alloy short fiber with 0.08 mm in diameter and 2 mm in length between 0 and 16wt%on the microstructure and mechanical properties of Ti（C,N）-based cermet were studied.The samples were prepared by powder metallurgy method.A series of equipments,such as OM,XRD and SEM,were used to observe and investigate the samples.The results show that,with the increase of the content of NiTi alloy short fiber,the flow ability is gradually lost,so the density of the green compact decreases.During sintering,most of Ni is evaporated or fonns Ni-Co solid solution,which results in the destruction of the atomic ratio of NiTi alloy.The liquid NiTi alloy diffuses into the interstice in the cermet.The interstice cann＇t be completely filled due to the low density of the green compact,thus pores are left inside of the cermet when cooled.The quantity of the pores increases with the increase of addition amount of the NiTi, thus the density and bending strength of the cermet decrease.