氮间隙固溶对CoCrFeMnNi高熵合金组织及性能的影响

在CoCrFeMnNi高熵合金制备过程中引入氮间隙固溶后进行轧制变形和1150℃1 h回复再结晶处理,研究了氮含量对高熵合金微观组织、力学性能和耐腐蚀性能的影响。结果表明:目前制备工艺条件下,氮均以固溶态存在于CoCrFeMnNi高熵合金中,无第二相析出。随着氮含量增加,合金的硬度提高,耐腐蚀性能提高。当氮含量为0.3wt%时,综合性能最佳,即显微硬度提高了约20.45%,腐蚀电流密度降低了约70.27%,浸泡腐蚀速率降低了约61.54%,浸点蚀坑的密度明显减少。

热处理对氮间隙固溶CoCrFeMnNi高熵合金组织及性能的影响

对60%轧制变形量的氮间隙固溶CoCrFeMnNi高熵合金分别进行800、900、1100℃下的热处理,研究了回复再结晶温度对高熵合金微观组织、力学性能和耐腐蚀性能的影响。结果表明,对合金进行不同温度的回复再结晶热处理后,合金的相结构没有改变。随着热处理温度增加,合金的硬度下降,塑韧性提高。当温度达到900℃时,晶粒发生再结晶,生成细小等轴晶粒,第二相弥散析出,此时合金具有较正的自腐蚀电位和较低的腐蚀电流密度,耐蚀性最好。

Effect of nitrogen on microstructure and mechanical properties of Cr Mn Fe VTi6 high entropy alloy

In order to evaluate interstitial strengthening effect on the properties of high entropy alloy(HEA),a nitrogen-doped Cr Mn Fe VTi6 HEA was fabricated by mechanical alloying(MA)and spark plasma sintering(SPS).XRD,SEM,TEM and FIB were used to characterize the phase composition and microstructure of this material.The sintered bulk HEA exhibits a microstructure comprising TiNx,BCC,Laves and B2 phases.The HEA exhibits high yield strength(>2729 MPa)and hardness in lower temperature range of<380℃.Quantitative calculations of the contributions from each strengthening mechanism in the BCC phase indicate that the interstitial strengthening by nitrogen is the dominant mechanism.Nitrogen additions in the BCC phase can produce a yield strength increase of-634 MPa/at.%,which is much higher than the strengthening effects of carbon or boron additions in other alloys.This demonstrates that adding nitrogen is a viable approach for enhancing the strength of HEAs.