摘要
研究了 Ti- 48Al+ (0 .2～ 0 .8) at% B合金中硼化物的生长机理。结果显示 :合金中的硼化物均为 C32结构的Ti B2 相 ;在加入 0 .2 at%和 0 .5 at% B的合金中只存在带状 Ti B2 相 ;而加入 0 .8at% B的合金中除带状 Ti B2 相外 ,还出现了少量六方形貌的块状 Ti B2 相。块状硼化物是从液相中自由生长的初生 Ti B2 相 ,其惯习面为 (0 0 0 1)基面和{ 10 10 }柱面 ;而带状硼化物则是次生 Ti B2 相 ,是通过 L→β+ Ti B2 和 L +β→α+ Ti B2 反应与基体耦合生长的非规则共晶反应产物。两种形貌的 Ti B2 颗粒均以台阶方式生长。
The growth mechanism of borides in the alloys Ti-48Al+(0.2 similar to0.8)at%B has been investigated. The results show that the borides in these alloys are TiB2 with C32 type crystal structure. The TiB2 particles are flaky in the alloys containing 0.2at%B and 0.5at%B, but there are a few hexagonal blocky borides besides flaky borides in the alloy containing 0.8at%B. The blocky borides are primary TiB2 phase with (0001) basal and (10 (1) over bar0) prismatic habit plans. The flaky borides are secondary TiB2 phase, which are irregular eutectic reaction products of L-->beta +TiB2 and L+beta-->alpha +TiB2, and coupling growth with matrix. The growth mechanism of blocky and flaky TiB2 is a ledge mechanism.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2001年第1期19-22,共4页
Rare Metal Materials and Engineering
