W_(16)Ti_(20)Ta_(20)V_(44)高熵合金的制备和性能表征

Preparation and Properties Characterization of W_(16)Ti_(20)Ta_(20)V_(44)High Entropy Alloy

针对核聚变堆中第一壁材料的需求,本文开展了低中子活化元素的W高熵合金的设计及制备研究。为了降低W的极高熔点对样品制备的不利影响,通过不同判据设计出低W含量的W_(16)Ti_(20)Ta_(20)V_(44)合金(at.%)。结合粉末烧结预合金化和真空电弧熔炼工艺,制备出成分均匀的W_(16)Ti_(20)Ta_(20)V_(44)合金样品。结果表明,该四元合金为体心立方的单相固溶体结构,受制备过程中冷却速率的影响,形成了枝晶和等轴晶两种不同的宏观组织;在1673 K温度以下不发生相变,显示出高的热力学稳定性;室温压缩强度达到2665 MPa,压缩应变超过30%,断裂方式以由沿晶断裂和穿晶断裂构成的脆性断裂为主。

The design and preparation of W high entropy alloy with low neutron active element were studied for the first wall materials of nuclear fusion reactor.In order to reduce the adverse effect of the high melting point of W on the sample preparation,W_(16)Ti_(20)Ta_(20)V_(44)alloy with low W content was designed by different criteria.W_(16)Ti_(20)Ta_(20)V_(44)alloy samples with uniform composition were prepared by powder sintering pre-alloying and vacuum arc melting.The results show that the four-element alloy is a bore-centered cubic single-phase solid solution structure.Due to the influence of cooling rate during the preparation process,two different macrostructures of dendritic and equiaxed crystal are formed.No phase transition occurs below 1673 K,showing high thermodynamic stability.The compressive strength at room temperature reached 2665 MPa,the compressive strain is more than 30%,and the fracture mode is mainly brittle fracture composed of intergranular fracture and transgranular fracture.