| In this paper, dynamic fracture experiment was done on split Hopkinson pressure bar apparatus using ZA35 alloy. Fracture process of specimen was analyzed and methods were put forward to correct factors, such as dispersion effect, displace effect of contact point between specimen and wedge and inertia effect, by which the calculated precision of the dynamic fracture energy was influenced. And dynamic fracture energy versus loading rate (U -K) curve was obtained.ZA35 alloy was employed to test its dynamic fracture toughness and dynamic fracture toughness versus loading rate (KId -K) curve was received. From the comparison of above two curves, it was suggested that the corrective methods were good and the energy after correction was the true dynamic fracture energy at high loading speed.Made use of the repairing methods, the effect of Zn-Al alloy microstructure and loading speed on the dynamic fracture energy has been studied. The specimens for experiments have been selected and used ZA8, ZA27 and ZA35 which have different organization with the Al content increasing. Under the different loading speed, fracture experiment was proceed on the Hopkinson bar. The results analysis indicated that it made the dynamic fracture energy and the loading speed sensitivity were increase gradually, that the microstructure was refining and the fractograph was changed from cleavage to dimple, with the Al content increasing. With the loading speed rise, the dynamic fracture energy of ZA8 was invariable for the cleavage of the fractograph and ZA27, ZA35 reduced because of the fractograph changing from dimple to quasi-cleavage and the loading speed sensitivity of alloy decreased gradually.
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