SHPB参数对激光增材制造AerMet100钢动态力学行为的影响

Effect of SHPB parameters on dynamic mechanical behavior of laser additively manufactured AerMet100 steel

侵彻类武器装备在毁伤作用前需要保持高的结构完整性,发展具有优异强韧性能的超高强度钢弹体材料已成为保障相关武器装备结构完整性的重要途径,理解侵彻过程中环境载荷参数变化下超高强度钢弹体材料的动态力学行为成为研究的重要目标。主要研究了分离式霍普金森压杆(SHPB)关键载荷参数(如撞击杆长度和发射气压)影响下强韧化热处理后激光增材制造AerMet100超高强韧钢试样的动态力学性能,并结合试验前后的微观组织结构演化及断口形貌特征,分析了该合金钢的动态断裂行为。结果表明,强韧化热处理激光增材制造AerMet100钢在动态压缩试验中表现出了明显的应变速率强化效应,例如在80 kPa和160 kPa下发射200 mm撞击杆,试样应变速率分别为(2 131±76) s^(-1)和(5 149±326) s^(-1),抗压强度随应变速率增加从(2 062±32) MPa升高到(2 301±69) MPa;使用160 kPa发射100 mm撞击杆时,得到试样在(7 250±409) s^(-1)的应变速率下抗压强度为(2 488±100) MPa,此应变速率和抗压强度均为试验中的最大值;80 kPa和160 kPa气压发射相同长度撞击杆得到两种试样的绝热温升之比约等于气压之比,即1∶2。动态压缩前后试样显微组织没有明显变化,未出现绝热剪切带;在所有测试当中仅有160 kPa发射200 mm撞击杆时试样发生45°剪切断裂,试样断裂应变速率为5 292 s^(-1),断裂强度为2 281 MPa;断口中发现了放射区和剪切唇,放射区为准解理断裂,剪切唇为韧性断裂。试验结果为激光增材制造AerMet100钢的动态力学性能测试方法提供了试验参考。

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(2131±76)s^(-1)and(5149±326)s^(-1),respectively,and the compressive strength increases from(2062±32)MPa to(2301±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(7250±409)s^(-1)is(2488±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 5292 s^(-1)and fracture strength of 2281 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.