退火温度对FeCoCrNiTi高熵合金组织及性能的影响

Effect of annealing temperature on microstructure and properties of FeCoCrNiTi high-entropy alloy

采用真空电弧熔炼法制备了FeCoCrNiTi高熵合金,随后分别在600、800和1000℃下对其进行真空退火处理。利用X射线衍射仪(XRD)、扫描电镜(SEM)、显微硬度计和万能材料试验机等研究了不同退火温度对FeCoCrNiTi高熵合金显微组织、硬度和压缩力学性能的影响。结果表明:铸态FeCoCrNiTi高熵合金的组织由FCC相和η相构成。当退火温度为600℃时,合金中检测到了C14 Laves相,在后续更高的退火温度下C14 Laves相仍存在。800℃退火处理后,部分FCC相转化为σ相。在1000℃退火时,合金的组织由FCC相、η相和C14 Laves相组成。退火处理使得合金的硬度明显高于铸态合金硬度,极限抗压强度随退火温度的升高先升高后降低。当退火温度为600℃时,合金显微硬度和极限抗压强度达到最高,分别为982.9 HV0.2和1344 MPa。

FeCoCrNiTi high-entropy alloy was prepared by vacuum arc melting method,and then it was subjected to vacuum annealing treatment at 600,800 and 1000℃respectively.The effect of different annealing temperatures on microstructure,hardness and compressive mechanical properties of the FeCoCrNiTi high entropy alloy was studied by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),microhardness tester and universal material testing machine.The results show that the microstructure of the as-cast FeCoCrNiTi high entropy alloy is composed of FCC phase andηphase.When the annealing temperature is 600℃,C14 Laves phase is observed in the alloy,and C14 Laves phase still exists at the subsequent higher annealing temperature.After annealing at 800℃,part of FCC phase is transformed intoσphase.When annealed at 1000℃,the microstructure of the alloy consists of FCC phase,ηphase and C14 Laves phase.Annealing treatment makes the hardness of the alloy significantly higher than that of the as-cast alloy,and the ultimate compressive strength first increases and then decreases with the increase of annealing temperature.When the annealing temperature is 600℃,the microhardness and ultimate compressive strength of the alloy reach the highest,which are 982.9 HV0.2 and 1344 MPa respectively.