In this study, aluminum alloy 7075 (AA7075) nanopowders were prepared by High-Energy Ball Milling (HEBM) in a bath of isopropyl alcohol. The process was investigated in different milling times and silicon carbides (SiC) reinforcement percentual. The effects of these parameters on the samples were characterized by X-ray diffraction (XRD), Laser Diffraction (LD), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The XRD analyses showed that as the grinding time increases, the micro deformation also increases, while the crystallite and particle size decrease until a constant value at 480 min. If the percentual of SiC reinforcement increases until 5 percent, there is a minimum change in the results compared to AA 7075 milling 480 min with no reinforcement. On the other hand, when the AA7075 was milled for 480 min and reinforced by 10 percent SiC, the best structural refinement result was achieved.

In this work, composite powders of aluminum alloy 7075 (AA7075) reinforced by 2 weight percent of nanosized particles of silicon carbide (SiC), titanium nitride (TiN), and zinc oxide (ZnO) were produced in a bath of isopropyl alcohol by high energy ball milling during 480 min at 25 ºC, 900 rpm, and Balls-to-Powder Weight Ratio (BPR) of 20:1. The techniques of X-Ray Diffraction (XRD), Laser Diffraction Method (LDM), Scanning Electron Microscopy (SEM), and microanalysis of Energy Dispersive Spectroscopy (EDS) were used to characterize the powders as received and processed. Then, the composites were hot extruded and characterized by XRD, SEM, and microhardness Vickers (HV). The milling process reduces the crystallite and particle size to around 30 nm and 10 µm, respectively. After extrusion, a fine microstructure and good consolidation were found for all bars, except for AA7075 as received. The ranging microhardness values were from 97 HV to 121 HV.

This paper present a thermomechanical study of actuators in form of helical springs made from shape memory alloy wires that can work as actuator and/or as sensor. These abilities are due to the martensitic transformation. This transformation is a diffusionless phase transition that occurs by a cooperative atomic rearrange mechanism. In this work, helical spring actuators were manufactured from Cu-Zn-Al shape memory alloy wires. The springs were submitted to constant tensile loads and thermal cycles. This procedure allows to determine thermoelastic properties of the shape memory springs. Thermomechanical properties were analyzed during 50 thermal cycles in the temperature range from 20 to 130 °C. Results of variations in critical transformation temperatures, thermoelastic strain and thermal hysteresis are discussed based on defects rearrangement and martensitic transformation theory.