Effect of Sm Doping on the Microstructure, Mechanical Properties and Shape Memory Effect of Cu-13.0Al-4.0Ni Alloy

The effects of rare earth element Sm on the microstructure, mechanical properties, and shape memory effect of the high temperature shape memory alloy, Cu-13.0Al-4.0Ni-xSm (x = 0, 0.2 and 0.5) (wt.%), are studied in this work. The results show that the Sm addition reduces the grain size of the Cu-13.0Al-4.0Ni alloy from millimeters to hundreds of microns. The microstructure of the Cu-13.0Al-4.0Ni-xSm alloys are composed of 18R and a face-centered cubic Sm-rich phase at room temperature. In addition, because the addition of the Sm element enhances the fine-grain strengthening effect, the mechanical properties and the shape memory effect of the Cu-13.0Al-4.0Ni alloy were greatly improved. When x = 0.5, the compressive fracture stress and the compressive fracture strain increased from 580 MPa, 10.5% to 1021 MPa, 14.8%, respectively. When the pre-strain is 10%, a reversible strain of 6.3% can be obtained for the Cu-13.0Al-4.0Ni-0.2Sm alloy.

Potential Complications of Percutaneous Vertebroplasty Combined with Interstitial Implantation of 125I Seeds for Metastatic Spinal Tumors: A Case Report and Literary Review

Percutaneous vertebroplasty is often used to acquire the stability of the spine and relieve the pain caused by osteoporotic vertebral compressive fracture (OVCF). 125I seeds have been used for application of local therapy for tumors. A combined treatment was reported in previous literatures. Thus, this case report is aimed at reporting a patient with an occurrence of delayed radioactive myelopathy, who accepted percutaneous vertebroplasty combined with interstitial implantation of 125I seeds for metastatic spinal tumors, and at reviewing the published literatures.

Microstructure and mechanical characterizations of graphene nanoplatelets-reinforced Mg–Sr–Ca alloy as a novel composite in structural and biomedical applications

In this study, the novel composites were fabricated by the introduction of Mg-0.3Sr-0.3Ca alloy as the matrix and addition of different amounts of graphene nanoplatelets (0.1, 0.2, and 0.4 wt.%) as reinforcement using a stir casting technique followed by homogenization and extrusion in order to improve the mechanical properties of the base alloy. Optimum weight percent of adding graphene nanoplatelets was 0.2 wt.%. The addition of 0.2 wt.% graphene nanoplatelets in the extruded Mg–Sr–Ca alloy led to the grain refinement (∼36%), the decrease of anisotropy (∼14%) and the lowest twin formation. Moreover, the tensile and compressive yield strengths and tensile and compressive fracture strains of extruded Mg-0.3Sr-0.3Ca/0.2GNP composite were enhanced by 22.8%, 66.7%, 43.1% and 28%, respectively. The load transfer was significant strengthening mechanism. The uniform dispersion of graphene nanoplatelets followed by the increase of non-basal slip and grain refinement improved tensile fracture strain. In addition to maintained factors, the increase of compressive fracture strain in the extruded Mg-0.3Sr-0.3Ca/0.2GNP composite was affected by local stresses caused by twins which resulted non-basal slip and conserved basal slip due to presence of twins. Simultaneously, enhancement of the strengthening and elongation efficiencies in both tensile and compressive tests was achieved in Mg-0.3Ca-0.3Sr/0.2GNP. The biocorrosion behavior of extruded Mg-0.3Sr-0.3Ca/0.2GNP composite was promoted by 11% compared with Mg-0.3Sr-0.3Ca alloy. Comparative plots indicated that the fabricated materials can be introduced as a new class of composites for the purpose of structural as well as biomedical applications.