CAJ | 학술논문

采用全自动控制往复喷射成形工艺制备直径为495 mm的大规格7055铝合金锭坯，经热挤压、2次锻压成形和双级固溶处理后，分别进行 T76(120℃/6 h+160℃/8 h)、T74(120℃/6 h+160℃/18 h)和 T73(120℃/6 h+160℃/30 h)双级时效处理，测定时效态锻件各取样部位的抗拉强度(σb)、屈服强度(σ0.2)和电导率(γ)，并与单级时效T6态(120℃/24 h)的锻件进行对比，研究时效制度对轮毂锻件各取样部位性能和断裂方式的影响。结果表明，随二级时效时间延长，锻件的抗拉强度与屈服强度均降低，屈强比也略有降低，但断裂韧性提高；在T74和T73时效状态下试棒拉断后为典型的韧性断裂；随二级时效时间延长，锻件的断裂韧性和电导率均呈升高趋势，并改变T6态下的脆性断裂特征，满足机轮的应用要求。
채용전자동공제왕복분사성형공예제비직경위495 mm적대규격7055려합금정배，경열제압、2차단압성형화쌍급고용처리후，분별진행 T76(120℃/6 h+160℃/8 h)、T74(120℃/6 h+160℃/18 h)화 T73(120℃/6 h+160℃/30 h)쌍급시효처리，측정시효태단건각취양부위적항랍강도(σb)、굴복강도(σ0.2)화전도솔(γ)，병여단급시효T6태(120℃/24 h)적단건진행대비，연구시효제도대륜곡단건각취양부위성능화단렬방식적영향。결과표명，수이급시효시간연장，단건적항랍강도여굴복강도균강저，굴강비야략유강저，단단렬인성제고；재T74화T73시효상태하시봉랍단후위전형적인성단렬；수이급시효시간연장，단건적단렬인성화전도솔균정승고추세，병개변T6태하적취성단렬특정，만족궤륜적응용요구。
The large-sized 7055 aluminum alloy billets with diameter of 495 mm were prepared by fully automatic controlled reciprocating spray forming technology. The tensile strength, yield strength and conductivity of 7055 forging under different aging treatment, including T76 (120 ℃/6 h+160℃/8 h), T74 (120℃/6 h+160℃/18 h), T73(120℃/6 h+160℃/30 h), were detected. The effect of different aging treatment on mechanical properties and fracture mode were studied, which were compared with the data of forging under T6(120℃/24 h) heat treatment stage. The results show that, with increasing aging time (≤30 h), both the tensile strength and yield strength decrease, the yield ratio is slightly decreases simultaneously, and the fracture toughness increases. In contrast to the brittle fracture under T6 heat treatment state, the test bars show typical feature of the ductile fracture under T74 and T73 aging treatment state after tensile test. The fracture toughness and the electrical conductivity increase with increasing the aging time. The wheel hub forgings under T74 and T73 state can meet the application requirement of tire.