摘要
利用金相观察、定量统计及透射电子显微镜分析,研究了含Ti和无Ti的Fe-40Ni合金在高温等温过程中的晶界迁移行为。结果表明:Fe-40Ni-Ti合金原始试样中存在两种析出,分别是凝固过程中形成的尺寸较大的Ti N颗粒及锻压过程中形成的应变诱导析出相,尺寸为10 nm左右。在1100℃等温30 min后,没有发现应变诱导析出相存在。直接观察结果则显示粗大的Ti N颗粒对晶界迁移有明显的阻碍作用,以类似于位错绕过析出颗粒的Orowan机制绕过Ti N颗粒,其主要原因可能是高温时晶界自由能明显各向同性,只有直接面对析出相的局部晶界受到析出相的阻碍,能够发生大曲率弯曲,晶界表现出较强的"柔性",此时析出粒子必然无法对其运动产生强烈的阻碍作用。
The metallographic observation,quantitative statistics and transmission electron microscope（ TEM） technique was used to investigate the grain boundaries migration of Fe-40 Ni alloy with and without Ti during isothermal holding at elevated temperatures. The results indicate that： there two kinds of particles in the as-forged samples are the larger Ti N particles coming from the solidified process and very fine strain-induced precipitates coming from the forging formation respectively. The size of the latter is smaller than 10 nm. After being held at 1100 ℃ for 30 min,no strain induced precipitates can be observed. The direct observation under microscope shows the Ti N particles hinder the grain boundaries migration obviously. The grain boundary bypasses the Ti N particles in a way similar to dislocations bypassing particles in Orowan mechanism. The explanation of above mentioned phenomena is that： the free energy of grain boundaries displays the anisotropy apparently at the elevated temperatures. Obvious bend occurs only at parts of grain boundaries encountering the precipitates. The grain boundaries are flexible results in decreased hinder effect of precipitates.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2015年第11期25-28,共4页
Transactions of Materials and Heat Treatment
基金
河北省杰出青年科学基金(E2012105005)
