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为了进一步提高Fe-6.5%Si合金的塑性变形性能,以1100℃保温1 h油淬处理后的Fe-6.5%Si合金为对象,重点研究了不同回火温度和保温时间下合金的有序结构回复和残余应力松弛行为及其对三点弯曲力学性能的影响。结果表明,合理的回火处理工艺可在有效抑制有序结构回复的情况下显著松弛合金的淬火残余应力,进而提升淬火试样的塑性变形性能。300℃回火60 min、400℃回火10 min和500℃回火10 min试样的最大弯曲断裂挠度与淬火态试样相比分别提高了20.7%,31.3%,21.8%。合金塑性变形性能提高的原因与回火处理导致合金无序-有序结构回复以及试样表面微观残余应力的松弛有关。以400℃回火处理保温10 min为例,合金试样的有序相畴尺寸由淬火试样的20~200 nm提高到50~300 nm,表面残余拉和压应力分别降低了16.5%和19.4%。
In order to further improve the plastic deformation properties of Fe-6.5% Si alloy, the optimal structure of Fe-6.5% Si alloy after 1100 h of oil quenching was investigated. The ordered structure of the alloy at different tempering temperature and holding time Response and Residual Stress Relaxation Behavior and Its Effect on Three Point Bending Mechanical Properties. The results show that reasonable tempering treatment can significantly relax the quenching residual stress of the alloy while effectively restoring the ordered structure recovery, and then enhance the plastic deformation properties of the quenched sample. The maximum flexural rupture deflection of specimens annealed at 300 ℃ for 60 min, tempered at 400 ℃ for 10 min and tempered at 500 ℃ for 10 min increased by 20.7%, 31.3% and 21.8% respectively compared with that of quenched specimens. The reason for the increase of the plastic deformation properties of the alloy is related to the tempering of the disordered-ordered structure of the alloy and the relaxation of microscopic residual stress on the sample surface. Taking tempering at 400 ° C for 10 min as an example, the ordered phase-domain size of the alloy sample increased from 20 to 200 nm to 50 to 300 nm and the residual tensile and compressive stresses decreased by 16.5% and 19.4%, respectively %.