雾化合金粉制备ODS钢的组织与性能

Microstructure and mechanical properties of ODS steel produced by atomization alloy powders

首先采用气体雾化方式制备氧化物弥散强化（Oxide dispersion strengthened,ODS）钢的合金粉,然后经短时球磨及热等静压烧结成形方法制备了氧化物弥散强化钢9Cr-ODS。采用电子背散射衍射（EBSD）、透射电镜（TEM）,三维原子探针（APT）和万能拉伸实验机等研究了9Cr-ODS钢的组织结构和力学性能。实验结果表明：9Cr-ODS氧化物弥散强化钢的组织为铁素体和马氏体的双相组织,组织中弥散分布着极高密度的纳米析出相。三维原子探针的结果表明9Cr-ODS钢中这些纳米析出相的尺寸小于5 nm、分布密度可以达到3.5×10^22/m^3,其中Y2Ti2O7相分布密度达到1.57×10^20/m^3,同时在其析出相中还发现一些尺寸稍大的CrTi2O5氧化物相。与典型的低活化铁素体/马氏体钢、ODS钢相比较,雾化合金粉制备的9Cr-ODS钢表现出更加优异的力学性能。

First,the alloy powder of oxide dispersion strengthened（ ODS） steel was prepared by gas atomization,and then the oxide dispersion strengthened steel 9 Cr-ODS was prepared by hot isostatic pressing forming method after short time ball milling using the alloy powder as raw materials. Microstructure and mechanical properties of the 9 Cr-ODS steel were studied by means of electron backscattered diffraction（ EBSD） technique,transmission electron microcopy（ TEM）,three-dimensional atomic probe tomography（ APT） and universal tensile tester. The results show that the microstructure of the 9 Cr-ODS steel is ferritie and martensite dual-phase structure,and there are very high density nanocrystalline precipitates in the microstructure. The results of APT show that the size of these nanocrystalline precipitates in the 9 Cr-ODS steel is less than 5 nm,and the distribution density can reach 3. 5 × 10^22/m^3,the phase density of Y2Ti2O7 reaches 1. 57 × 10^20/m^3,at the same time,some larger CrTi2O5 oxide phases are also found in the microstructure. Compared with the typical low activation ferrite/martensitic steel and ODS steel,the 9 Cr-ODS steel produced by atomization alloy powder shows better mechanical properties.