TaWTiVCr高熵合金薄膜的制备及微观结构、力学性能研究

Study on Preparation,Microstructure and Mechanical Properties of TaWTiVCr High Entropy Alloy Thin Film

目的使用磁控溅射设备进行共沉积,制备不同元素组成的TaWTiVCr高熵合金薄膜,并对薄膜力学性能进行表征,为该体系高熵合金最佳元素组成的筛选提供依据。方法在共沉积中,通过对TaW和TiVCr两组中间合金靶的沉积电流进行调整,实现薄膜元素组成的调整。使用X射线衍射仪(XRD)、扫描电镜(SEM)、能量色散X射线光谱仪(EDX)和原子力显微镜(AFM),研究了不同元素组成下薄膜的表面形貌、粗糙度、元素组成及相结构的变化。使用纳米压痕法分析了材料的硬度和模量,通过往复磨损实验分析了材料的耐磨性,使用共聚焦显微镜(CLSM)计算磨损体积,同时将力学性能的实验数据以及热力学计算的结果相结合进行分析。结果随Ti、V、Cr含量的增加,薄膜结晶性能变差,由BCC晶体结构向BCC+非晶态混合结构转变,表面形貌由褶皱状形貌转变为凹坑状形貌,并伴有微小团聚颗粒形成。硬度和模量先升高,随后下降,其中Ta24W25Ti16V18Cr17薄膜在多种强化机制的作用下,表现出最好的力学性能,硬度和模量分别达到27.61 GPa和274.42 GPa。同时受较高的硬度和特殊表面形貌特征影响,薄膜表现出较低的平均摩擦系数和磨损率,分别为0.34和5.01×10^−9 mm^3/(N·mm),具备优异的耐磨性能。结论通过共沉积法制备高熵合金薄膜并进行表征,可以快速筛选出TaWTiVCr高熵合金的最佳元素组成,在特定的元素组成下,形成BBC和非晶态混合结构有助于提高材料的力学性能。

The work aims to prepare TaWTiVCr high-entropy alloy thin films with different element compositions by co-deposition with magnetron sputtering equipment,and characterize the mechanical properties of the films,to provide screening basis for optimal alloy element composition.The elemental compositions of thin film were adjusted by tuning the deposition currents of the two TaW and TiVCr targets.X-ray diffractometer(XRD),scanning electron microscope(SEM),energy dispersive X-ray spectrometer(EDX)and atomic force microscope(AFM)were used to study the surface morphology,roughness,elemental composition,and phase structure of the film with different elemental compositions.The nanoindentation method was used to analyze the hardness and modulus of the material.The wear resistance of the material was analyzed by reciprocating wear experiments,and the wear volume was calculated with Confocal Laser Scanning Microscope(CLSM).At the same time,the experimental data of mechanical properties and the results of thermodynamic calculations were combined for analysis.With the increase of Ti,V,and Cr content,the crystallinity deteriorated,and transformed from BCC crystal structure to BCC+amorphous mixed structure.The surface morphology changed from a fold-like morphology to a pit-like morphology,with the formation of tiny agglomerated particles.The hardness and modulus firstly increased and then decreased.Ta24W25Ti16V18Cr17 film had the best mechanical properties under the action of multiple strengthening mechanisms,and the hardness and modulus reached 27.61 GPa and 274.42 GPa,respectively.At the same time,due to higher hardness and special surface morphology,the film showed a lower average friction coefficient and wear rate of 0.34 and 5.01×10^−9 mm^3/(N·mm),respectively and had excellent wear resistance.Preparation and characterization of high-entropy alloy films by co-deposition method can quickly screen the optimal elemental composition of TaWTiVCr high-entropy alloys.Under the specific elemental composition,the formation of BBC and amorphous mixed structure helps to improve the mechanical properties of the material.