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采用Gleeble-3800热模拟试验机对晶粒尺寸为200～250 nm的复合细化超细晶纯锆在变形温度为300～450℃,应变速率为0.001～0.05s-1的范围内进行单向热压缩实验.结果表明:热加工参数对超细晶纯锆流动应力影响很大.通过实验数据以及显微组织分析可知,在较高的变形温度和较低的应变速率下更容易发生动态再结晶;构建了超细晶纯锆的临界应变模型,得出其温度补偿应变速率因子Z与εc(临界应变),σc(临界应力),εp(峰值应变)和σp(峰值应力)间的关系;建立了超细晶纯锆动态再结晶体积分数模型,可以看出其动态再结晶发生的阶段为应变0.1～0.45.“,”An ultrafine-grained(UFG)pure zirconium refined by compounding with grain size of 200～250 nm was subjected to a unidirectional compression test using a Gleeble-3800 thermal simulation tester at the temperatures of 300～450℃and strain rates of 0.001～0.05 s-1.Experimental results show that the hot process parameters influence the flow stress of the UFG pure zirconium.Experimental data and microstructure analysis reveal that dynamic recrystallization is more likely to occur at higher deformation temperatures and lower strain rates.The critical strain model of UFG pure zirconium was established,and the relationship between the temperature-compensated strain rate factor Z and εc(critical strain),σc(critical stress),εp(peak strain)and σp(peak stress)was obtained.The constitutive model of UFG pure zirconium was confirmed based on dynamic recrystalization(DRX)volume fraction and proven to occur at a strain of 0.1 to 0.45.