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在440℃经多向锻造加工成7075铝合金锻件。研究了锻件的显微组织和力学性能随退火温度和T73回火的变化,TEM和SEM用于分析锻件的晶粒和第二相形态。多向和大变形锻造产生平均晶粒尺寸1.8μm的完全再结晶组织。390℃～450℃退火使晶粒长大到3μm,但位错和第二相分布没有明显改变,这时锻件展现出较低强度和较高延性。T73回火使锻件屈服强度和拉伸强度分别提高280%和210%,而延性同退火样相比并无明显下降,断裂韧性达到51MPam12,可以认为这是沉淀强化的贡献。
At 440 ℃ by multi-directional forging processed into 7075 aluminum forgings. The microstructures and mechanical properties of forgings were studied with the annealing temperature and T73 tempering. TEM and SEM were used to analyze the grain shape and the morphology of the second phase. Multi-directional and large deformation forging produces fully recrystallized tissue with an average grain size of 1.8 μm. Annealing at 390 ℃ ~ 450 ℃ increased the grain size to 3μm, but the dislocation and the distribution of the second phase did not change obviously. At this time, the forging showed lower strength and higher ductility. T73 tempering forging yield strength and tensile strength were increased by 280% and 210%, respectively, while the ductility and annealing samples did not significantly reduce the fracture toughness reached 51MPam12, can be considered that this is the contribution of precipitation strengthening.