MA-SPS法制备WTaCrVTi难熔高熵合金的组织结构与力学性能

Microstructure and Mechanical Properties of WTaCrVTi High-Entropy Alloy Prepared by Mechanical Alloying and Spark Plasma Sintering

摘要:

采用机械合金化-放电等离子烧结（MA-SPS）法制备W_23.5Ta_23.5Cr_23.5V_23.5Ti₆难熔高熵合金，探索球磨时间对合金的元素分布及组织结构的影响。研究发现，经过40 h球磨后的粉末，颗粒尺寸大小一致，为3.65±1.91 μm，并呈现等轴颗粒形貌，经1500 ℃的SPS烧结，得到了致密的、组织均匀的合金。其中bcc结构的WTaCrVTi_x固溶体连续分布，W、Ta、Cr和V的原子比接近等原子比；少量的Laves相弥散分布在基体中；fcc结构的TiO颗粒的平均尺寸为1.08±0.38 μm，均匀分布在基体中。合金的室温/高温压缩屈服强度和显微硬度分别为2870、1954 MPa和873.4±7.6 HV。

Abstract:

Mechanical alloying combined with spark plasma sintering (MA-SPS) was adopted to prepare W_23.5Ta_23.5Cr_23.5V_23.5Ti₆ high-entropy alloys. The effects of ball milling durations on the elemental distribution and microstructure of the alloys were explored. Results show that the powder after 40 h ball milling has a homogeneous particle size with 3.65±1.91 μm, and presents an equiaxed particle morphology. The dense and uniform alloy can be obtained after SPS at 1500 ℃. The WTaCrVTi_x solid solution with bcc structure is continuously distributed, in which the atomic ratios of W, Ta, Cr and V are close to the equiatomic ratios. A small amount of Laves phase is distributed in the matrix. The TiO particles with fcc structure have an average size of 1.08±0.38 μm and are uniformly distributed in the matrix. The room-temperature compressive yield strength, high-temperature compressive yield strength and microhardness of the alloy are 2870, 1954 MPa and 873.4 ±7.6 HV, respectively.