Al 量对 Ni-Al-Hf-Cr-W 系合金显微组织结构的影响

 研究了Ni-20Hf-8Cr-8W-（4～6）Al系列合金的显微组织以及Al含量对共晶组织的影响，结果表明：此系列合金中，随着Al含量的微小变化，会析出不同的共晶组织；当Al含量大于5.5wt%时，出现（β-NiAl+Ni7Hf2）或（γ′+β-NiAl+Ni7Hf2）共晶：当Al量小于5.5wt%时，会出现（γ′+Ni7Hf2）、（γ+γ′+Ni7Hf2）或（γ+Ni7Hf2）共晶组织。并且得出（Ni-20Hf-8Cr-8W-5.3Al）wt%的合金具有（γ′+Ni7Hf2）共晶，适宜选做为以Ni7Hf2增强的共晶复合材料的合金成份。

EFFECT OF Al CONTENT ON MICROSTRUCTURE OF Ni Al Hf Cr W SYSTEM ALLOYS

The microstructural characterizations of Ni (4～6)Al 20Hf 8Cr 8W system alloys have been examined by optical micrograph,TEM,SEM,Electron Microprobe and X ray diffraction. In particular, the influence of aluminium content was studied in detail. A slight difference of the aluminum content can change obviously the microstructure and bring about eutectic phases. The γ′+Ni 7Hf 2,γ+γ′+Ni 7Hf 2 or γ+Ni 7Hf 2 eutectic was present in low Al content alloys(<5.5wt%) ,and the β+Ni 7Hf 2 or γ+β NiAl+Ni 7Hf 2 eutectic in high content alloys(>5.5 wt%) . Ni 5.3Al 20Hf 8Cr 8W is the proper composition as the γ′/Ni 7Hf 2 eutectic composite materials.