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测定了沉淀硬化型模具钢１０Ｎｉ３ＭｎＣｕＡｌ在不同加载速率ｖ０下动态断裂韧性Ｋ１ｄ．试验结果表明，随着ｖ０的提高，Ｋ１ｄ降低．ＳＥＭ断口观察揭示，随冲击加载速率的提高，断口形式由韧窝准解理逐渐转变为沿晶准解理形貌．理论研究结果表明，Ｋ１ｄ与裂纹尖端塑性区内参与微裂纹形核的第二相粒子有关．被激活而参与微观断裂的沉淀析出物越多，Ｋ１ｄ越小．透射电镜的微结构分析显示，标准时效（４ｈ）或初时效（１０ｍｉｎ）状态下，其沉淀析出物为大量弥散的金属间化合物Ａｌ３Ｎｉ．沉淀析出物的数量、形态及尺寸分布是影响动态断裂韧性的主要原因．
The dynamic fracture toughness K1d of the precipitation hardened die steel 10Ni3MnCuAl at different loading rates v0 was measured. The experimental results show that as v0 increases, K1d decreases. The observation of SEM fracture reveals that with the increase of impact loading rate, the fracture form changes from quasi-cleavage dimple to cleavage morphology. The theoretical results show that K1d is related to the second phase particles involved in microcracking nucleation in the plastic zone of crack tip. The more precipitate precipitates are activated and participate in the microscopic fracture, the smaller K1d. TEM analysis of microstructures showed that precipitation precipitation was a large amount of dispersed intermetallic compound Al3Ni under standard aging (4h) or initial aging (10min). The amount, shape and size distribution of precipitates are the main factors affecting the dynamic fracture toughness.