摘要
自生颗粒增强钛基复合材料中的TiC增强相,可分为初生TiC和共晶TiC,它们的形态、尺寸及形成机制均不尽相同。利用SEM、XRD、EDX等手段研究了钛合金中共晶TiC的形态及形成机制。合金中含碳量不同时,可能形成规则共晶或离异共晶。成分处于共晶点附近的合金,由于两相共生生长,β-Ti抑制了TiC的分枝,使TiC呈棒状或颗粒状,形成规则共晶。含碳量远低于共晶成分时易形成离异共晶,共晶反应发生在初生β-Ti枝晶的间隙中,多数共晶β-Ti依附于初生β-Ti生长,TiC与熔体接触增多,易分枝,而大量初生β-Ti的存在使TiC分枝受空间限制,只能在二维方向上分枝,从而促使羽毛状TiC的形成。Mo、Sn等合金元素的加入可使共晶TiC形态成为球团状。
TiC can be divided into two kinds of primary TiC and eutectic TiC in the Ti-matrix composites reinforced with in-situ particles. The morphology, size and forming mechanism of the primary TiC differ from the and eutectic TiC, In this paper, the forming process and morphologies of the eutectic TiC in Ti alloys were studied by using of SEM, XRD and EDS. For different C contents in the Ti-C alloy, regular eutectic TiC or divorced eutectic TiC can exist. In the alloy with a composition neat the eutectic point of Ti-C alloy, the TiC morphology is rod-shape and particle-shape due to the co-growth of two phases beta-Ti and TiC and the suppression of beta-Ti dendrite. When the C content in Ti-C alloy is lower than the eutectic point. greatly, the alloy forms the divorced eutectic between beta-Ti dendrites growing and clung to the primary beta-Ti. Although the TiC tends to the branch during growing, the beta-Ti dendrites restrain the free,growth only in two dimensions and with feather shape for the TiC dendrite; The feather-shaped TiC can be changed to be spherical shape by adding of elements, such as Mo and Sn.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2003年第6期451-455,共5页
Rare Metal Materials and Engineering
基金
金属精密热加工国防科技重点实验室开放基金项目(99JS61.5.1.ZS6102.)
