微量稀土Y对AlCrMo0.5NbV体系难熔高熵合金组织和性能的影响OA

A series of refractory high-entropy alloys(AlCrNbMo0.5V)100-xYx containing trace rare earth Y were prepared via vacuum arc melting,and the effects of Y on the microstructure and properties of(AlCrNbMo0.5V)100-xYx alloys were systematically investigated.The results show that all of the alloys have a single body-centered cubic(BCC)structure,and the variation of Y content does not affect the phase composition of the(AlCrNbMo0.5V)100-xYx alloys.When the Y content is relatively low(≤0.3at.%),each element distributes uniformly;when the Y content increases to 0.45at.%,the element Y generates segregation and precipitation because it exceeds the solid solubility limit of the alloy.The high-temperature compression test under 1 273 K shows that when the Y content is 0.15at.%,the yield strength and peak strength of the alloy reach the maximum values(632 MPa,716 MPa),which are 30.4%and 10.8%higher than those of the alloy without Y,respectively,however,the fracture strain decreases from>50%to 45.8%.Analysis shows that an appropriate amount of Y enhances the strength through solid solution strengthening caused by lattice distortion,but it inhibits the dislocation slip,resulting in the plasticity decrease;excessive Y content will lead to segregation of Y and form brittle phases,weakening the strengthening effect and resulting in the plasticity decrease.