摘要
采用高分辨透射X射线三维成像技术研究了传统高速凝固法(HRS)和液态金属冷却法(LMC)两种工艺制备的镍基单晶高温合金DD33中显微孔洞的三维尺寸信息,结果表明:与HRS相比,LMC工艺降低一次枝晶间距,增加共晶体积分数,使最后凝固阶段枝晶间的空隙尺寸变大,压降降低,最终降低了铸态孔的尺寸及体积分数。固溶处理后用两种工艺制备的合金中显微孔洞的体积分数都有所增加,但是用LMC工艺制备的合金中较细的枝晶和较低的偏析程度,使合金中固溶孔的体积分数显著低于用HRS工艺制备的合金。
Microporosity in a single crystal nickel-based superalloy DD33 solidified by high rate solidification(HRS) and liquid metal cooling(LMC) process was investigated by the X-ray tomography(XRT).It is found that the pressure drop was reduced because of the larger volume fraction of eutectic in the alloy solidified by LMC, which results in less solidification-pore(S-pore) formation. Homogenization-pore(Hpore) forms in interdendritic regions during solution heat treatment, which results in the increase of volume fraction of porosities during heat treatment. However, lower level of H-pore in the LMC samples can be attributed to the finer dendrite arm spacing and the lower segregation.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2014年第9期656-662,共7页
Chinese Journal of Materials Research
基金
国家重点基础研究发展计划项目2010CB631201
国家自然科学基金51201164
国家高技术研究发展计划项目2012AA03A511~~
