激光立体成形Ti-25V-15Cr合金的阻燃性能

Burn-Resistant Property of Laser Solid Forming Ti-25V-15Cr Alloy

研究了激光立体成形(laser solid forming,LSF)Ti-25V-15Cr合金的阻燃性能。采用直流电弧激发燃烧法(direct current simulation burning,DCSB)测试其阻燃性能并与锻造Ti40合金进行比较。基于二者原始组织、燃烧产物的观察与分析揭示其阻燃机理。结果表明,激光立体成形Ti-25V-15Cr合金的燃烧速率略低于锻造Ti40合金。燃烧后各区域组织分析表明,激光立体成形Ti-25V-15Cr合金和锻造Ti40合金燃烧产物区均由Ti的氧化物、V的氧化物以及基体组成,Ti-25V-15Cr合金燃烧产物区氧化物面积略小于锻造Ti40合金,同时燃烧热影响区的晶界和亚晶界处发现明显的V、Cr元素的偏聚。激光立体成形Ti-25V-15Cr合金中局部枝晶组织以及亚晶粒的形成增加了微观结构的缺陷,在受热条件下使得V、Cr元素的扩散能力增强,是其抗燃烧性能略优于锻造Ti40合金的原因。

The burn-resistant property of laser solid forming（LSF） Ti-25V-15Cr alloy was studied, and compared with that of forging Ti40 alloy. The burn-resistant mechanism was disclosed by combining the analysis of the microstructure of the alloy and the combustion products. The results show that the burning rate of Ti-25V-15Cr alloy is slightly lower than that of forging Ti40 alloy. The combustion products of Ti-25V-15Cr alloy and Ti40 alloy are mainly composed of a mixture of Ti oxide and V oxide, and the substrate. The area of the oxide in the combustion product zone of LSF Ti-25V-15Cr is slightly smaller than that of forging Ti40 alloy. Moreover, the distinct segregation of V and Cr at the grain boundary and subgrain boundary in the heat affected zone is found in LSF Ti-25V-15Cr alloy. The formation of the dendrites and subgrains in LSF Ti-25V-15Cr alloy increases the micro-defect and leads to the better diffusion capacity of V and Cr, which is responsible for the better resistance to burning of LSF Ti-25V-15Cr than that of forging Ti40.