In this study, tungsten heavy alloys reinforced with highly uniform and dispersed nanosized Zr(Y)O2 particles were investigated. These alloys exhibited a high compressive strength and enhanced plasticity. To fabricate these alloys, we used a novel process involving molecular level liquid-liquid doping combined with hot isostatic pressing. The Zr(Y)O2 particles thus produced were smaller than 200 nm in size and bonded well with tungsten grains. The size of Zr(Y)O2 particles and tungsten grains are much smaller than those of the state-of-the-art review and the details of the grain refinement mechanisms were discussed. The highest ultimate tensile and compressive strengths of the fabricated alloys at room temperature (27°C) were 895 and 1445 MPa, respectively, which are much higher than the values reported in the literature. The tensile fracture surface consists of W - W cleavage patterns and ductile failure of the matrix. The effect of Zr(Y)O2 particles and strain rate on the compressive properties of the alloys was investigated in detail and the corresponding compressive deformation mechanisms were elucidated.