Manufacturing Bulk Nanocrystalline Al-3Mg Components Using Cryomilling and Spark Plasma Sintering

Abstract

In the current study, pure aluminum (Al) powders were cryomilled with and without 3 wt.% pure magnesium (Mg) dopant for varying durations followed by spark plasma sintering (SPS) of powders to prepare bulk components with superior mechanical properties. The crystallite sizes were determined for powders and the bulk components by analyzing the X-ray diffraction (XRD) spectrum. The calculations indicated a reduction in crystallite size with the increase in the cryomilling duration. The results also showed a more significant decrease in the crystallite sizes for Al-3Mg samples than that of pure Al. The changes in the surface morphology of powders were characterized using scanning electron microscopy (SEM). The elemental mapping analysis at nanoscale was carried out using Energy-dispersive X-ray spectroscopy (EDX) in Scanning transmission electron microscopy (STEM). The mechanical properties of the bulk components were assessed using a Vickers Microhardness tester. The test results demonstrated an improvement in the hardness of Mg-doped components. Higher hardness values were also reported with an increase in the cryomilling duration. This article discusses the mechanisms for the reduction in crystallite size for pure Al and Al-3Mg and its subsequent impact on improving mechanical properties.

Flexible and Form-Stable Phase Change Composites Enabled by Pinecone-like Structure for Efficient Thermal Management

“…35 For Al powders, there are four diffraction peaks at 38.6°, 44.8°, 65.2°, and 78.3°c orresponding to the (111), ( 200), (220), and (311) crystal planes of Al, respectively. 36,37 The pattern of the PA composite has the diffraction peaks of PSV-30 and Al, the pattern of the PE composite contains the diffraction peaks of PSV-30 and EG, and the pattern of the PEA-5 composite exhibits all of the main diffraction peaks of PSV-30, EG, and Al. Hence, these above results indicate that the PA, PE, and PEA-5 composites are physical mixtures, and their crystal structures remain basically unchanged.…”

Aluminium-Silicon Lightweight Thermal Management Alloys with Controlled Thermal Expansion

“…Mechanical alloying was first developed in the 1960s with the aim of fabricating a nickel-based superalloy with homogeneous distribution of oxide reinforcements for gas turbine applications [13]. Since then, many material combinations have been explored [14][15][16][17][18][19][20][21][22][23][24][25][26]. The basic principle is the cyclical welding and fracture of ductile and brittle powders via repetitive impact, resulting in a distribution of reinforcement within the metallic matrix particles [27].…”

Crystallization and Assembly-Driven Nanostructures for Energy, Electronics, Environment, and Emerging Applications

“…(iii) Controlling the crystalline components of inorganic materials attracts an intense scientific interest, in efforts to achieve optimization in crystallography, crystallization process (including dynamics), hierarchical morphology, nanostructure, nanopattern, or assembly-driven interfaces and composites. These changes largely contribute to the further enhancements in mechanical, ionic, electronic, and other functional behaviors of current-generation inorganic nanomaterials [ 3 , 4 , 5 ]. For example, Ultrasonic nanocrystalline surface modification represents a unique approach for mechanical impact-based surface deformation [ 3 ].…”

“…It has the potential towards gradient nanostructured surface layers, which can be impactful in the future generation of transportation, energy, medical, and chemical industries. Cryomilling and Spark Plasma Sintering are among other important approaches for enhancing the crystallites and properties of pure [ 4 ] and composite inorganics [ 5 ].…”