SHPB 参数对激光增材制造 AerMet100 钢动态力学行为的影响

The maintenance of high structural integrity is essential for penetrating-type weapon systems before their destructive action. The development of ultra-high-strength steel materials with excellent toughness has become a crucial approach to ensure the structural integrity of relevant weapon systems. Understanding the dynamic mechanical behavior of ultra-high-strength steel materials under changing environmental load parameters during penetration is an important study objective. The dynamic mechanical properties of laser additively manufactured ultra-high strength and toughness AerMet100 steel specimens under critical load parameters（such as striker length and launching pressure）were primarily investigated using a Split Hopkinson Pressure Bar（SHPB），and combined with the analysis of microstructure evolution and fracture morphology characteristics before and after the test，the dynamic fracture behavior of the alloy steel was grasped. The results show that the strain rate hardening effect of laser additively manufactured AerMet100 steel is obvious in the dynamic compression experiment. For example，when 200 mm striker bar is launched at 80 kPa and 160 kPa，the strain rates of the samples are（2 131±76）s^-1 and（5 149± 326）s^-1，respectively，and the compressive strength increases from（2 062±32）MPa to（2 301±69）MPa with the increase of strain rate. When 160 kPa is used to launch a 100 mm striker bar，the compressive strength of the sample at（7 250±409）s^-1 is（2 488±100）MPa，and the strain rate and compressive strength are both the maximum values in the experiment. The ratio of adiabatic temperature rise between the two specimens obtained with the same striker launched at 80 kPa and 160 kPa is approximately equal to the ratio of gas pressures，i. e. ，1∶2. There is no significant change in the microstructure of the specimens before and after dynamic compression，and no adiabatic shear bands are observed. Among all tests，only when a 200 mm striker bar is launched at 160 kPa，the specimen undergoes 45° shear fracture，with fracture strain rate of 5 292 s^-1 and fracture strength of 2 281 MPa. Radiative zones and shear lips are found on the fracture surface，with the radiative zone exhibiting quasi-cleavage fracture and the shear lip exhibiting toughness fracture. The experimental results provide a reference for testing the dynamic mechanical properties of AerMet100 steel made by laser additive manufacturing.