Effects of Sb and heat treatment on the microstructure of Al-15.5wt%Mg_2Si alloy

The modification effects of alloying element Sb and heat treatment on Al-15.5wt%Mg2Si alloy were investigated by Olympus microscopy （OM）, scanning electron microscopy and energy disperse spectroscopy （SEM-EDS）, and X-ray diffraction （XRD）. It is found that Sb plays a significant role in shaping primary Mg2Si phase and eutectic Mg2Si phase in Al-15.5wt%MgzSi alloy. The Sb addition of about 1.0wt% makes the resultant alloy show the finest primary Mg2Si phase and the eutectic Mg2Si phase with well distribution. But further increasing the Sb content decreases the amount of primary Mg2Si phase, and some segregated phases appear at regions between the grains. In addition, heat treatment can modify the microstructural feature of Sb-modified Al-15.5wt%Mg2Si alloy in terms of obviously shortening the nodulizing time of primary Mg2Si phase and eutectic Mg2Si phase.

Exploration of Al-based matrix composites reinforced by hierarchically spherical agents

Al-based composites reinforced with A1-Ti intermetallic compounds/Ti metal hierarchically spherical agents were successfully fabricated by powder metallurgy. This kind of structure produces strongly bonded interfaces as well as soft/hard/soft transition regions between the matrix and reinforced agents, which are beneficial to load transfer during deformation. As expected, the resultant composites exhibit promising mechanical properties at ambient temperature. The underlying mechanism was also discussed in this paper.

Positron emission tomography and magnetic resonance imaging combined with computed tomography in tumor volume delineation: A case report

BACKGROUND Accurate delineation of the target area for patients with hypopharyngeal cancer is the key to achieving an ideal radiotherapy effect.Since computed tomography(CT)alone can no longer meet the treatment needs,fusing CT images with magnetic resonance imaging(MRI)or positron emission tomography(PET)images can overcome the disadvantages of CT.Herein,we present a clinical case of hypopharyngeal cancer to delineate the tumor volume using combined MRI-CT and PET-CT fusion images to examine if they could accurately cover the tumor volume.CASE SUMMARY A 67-year-old male patient with hypopharyngeal carcinoma could not tolerate chemotherapy and surgery due to complicated health issues such as diabetic nephropathy and other underlying diseases.After multidisciplinary consultations,clinicians eventually agreed to undergo radiotherapy to control the progression of his tumor.He was examined by CT,MRI,and 18-fluorodeoxyglucose-PET for treatment planning,and CT images were fused with PET and MRI images while delineating tumor volume.CONCLUSION The image fusion of MRI-CT and PET-CT has both advantages and disadvantages.Compared with CT images alone,the combination of MRI-CT and PET-CT fusion images can precisely cover the gross tumor volume in hypopharyngeal carcinoma and avoid overestimation or incomplete coverage of tumor volume.

Microstructure and mechanical properties of Al-5.5Fe-1.1V-0.6Si alloy solidified under near-rapid cooling and with Ce addition

Al-Fe-V-Si alloys were developed for use at elevated temperature and usually produced through a rapid solidification-powder metallurgy route. In this work, effort was made to produce the material via casting route. The studied alloys were cast under the condition of near-rapid cooling. The influence of Ce addition on microstructure and mechanical properties of near-rapid solidified alloys were investigated. The results indicate that the as-cast microstructure of Al-5.5 Fe-1.1 V-0.6 Si alloy is significantly refined when the alloy was solidified under nearrapid cooling. Adding Ce results in the further refinement of intermetallic compound and the formation of an Al-V-Ce phase which replaces the primary phase Al(Fe,V)Si. The mechanical properties of the alloy are significantly improved by Ce addition: More than 70% increase in tensile strength and elongation is achieved by adding 1.00 wt% Ce to the alloy. It is concluded that near-rapid cooling and Ce addition are effective in improving mechanical properties of cast Al-5.5 Fe-1.1 V-0.6 Si alloy.