The intensity and position of sidebands (satellites) on both sides of main diffraction peak in a great number of X-ray diffraction profiles of alloys always change with progress of aging. The sidebands position is determined by a newly optimized Voigt function in present investigation. Furthermore, for Cu-4 wt pct Ti alloy aged at 400℃ for 720 min and 1080 min, after introducing the weight factor of above two satellites intensity, the relative error between the fitting curves and X-ray diffraction profiles is less than 0.185%, which is more precise than the previously calculating result.
The influence of double aging on the microstructure and mechanical properties of ultrahigh strength steel Aermet100 was analyzed. Under the double aging, there is no apparent decrease in the strength of steel. However, theimpact fatigue life can be prolonged by 35.5% and dynamic fracture toughness be raised by 22.6% respectively, ascompared with the normal aging. Based on the observation of microscopic structure, the physical mechanism ofthe prolongation of impact fatigue life and the enhancement of stability of the reverted austenite, AR, is analyzedfurther. The results show that this new technique is a breakthrough of combination optimization between strengthand toughness for Aermet 100 steel. In the light of the current understanding on this subject, the volume fractureof soften and tough AR formed in process of heat preservation at higher temperature of double aging increasesdrastically. Moreover, during the treatment of lower temperature of double aging, the carbon separating from themartensitic ferrite will diffuse into AR, resulting that the martensitic brittleness decreases and the stability of ARincreases.
