The effect of milling time on the alumina phase transformation in the AMCs powder metallurgy reinforced by silica-sand-tailings

This study aims to determine the effect of milling time and sintering temperature parameters on the alumina transformation phase in the manufacture of Aluminium Matrix Composites (AMCs) reinforced by 20 % silica sand tailings using powder metallurgy technology. The matrix and fillers use waste to make the composites more efficient, clean the environment, and increase waste utilization. The milling time applied to the Mechanical Alloying (MA) process was 0.5, 6, 24, 48, and 96 hours, with a ball parameter ratio of 15:1 and a rotation of 93 rpm. Furthermore, hot compaction was carried out using a 100 MPa two-way hydraulic compression machine at a temperature of 300 °C for 20 minutes. The temperature variables of the sintering parameter process were 550, 600 to 650 °C, with a holding time of 10 minutes. Characterization of materials carried out included testing particle size, porosity, X-Ray Diffraction (XRD), SEM-Image, and SEM-EDX. The particle measurement of mechanical alloying processed, using Particle Size Analyzer (PSA) instrument and based on XRD data using the Scherrer equation, showed a relatively similar trend, decreasing particle size occurs when milling time was increased 0.5 to 24 hours. However, when the milling time increases to 48 and 96 hours, the particle size tends to increase slightly, due to cold-weld and agglomeration when the Mechanical Alloying is processed. The impact is the occurrence of the matrix and filler particle pairs in the cold-weld state. So, the results of XRD and SEM-EDX characterization showed a second phase transformation to form alumina compounds at a relatively low sintering temperature of 600 °C after the mechanical alloying process was carried out with a milling time on least 24 hours

Development of TiB and nanocrystalline Ti-reinforced novel hybrid Ti nanocomposite produced by powder metallurgy

Titanium monoboride (TiB) whisker-reinforced titanium (Ti) matrix composites were produced by powder metallurgy, through vacuum sintering. TiB is formed by thermal decomposition of TiB2 precursor. In addition, a new hybrid composite was developed by admixing nanograined and nanocrystalline (more important) Ti to enhance the transformation mechanism of TiB2 to TiB phase. The morphology and particle size of the initial powders, mixtures and the microstructure of the composites have been studied by scanning electron microscopy (SEM). The phase analysis and transformation monitoring were performed by X-ray diffraction (XRD). The sintered composites were also subjected to compressive strength and hardness measurements. According to XRD results, through the addition of nanocrystalline Ti, a probable enhancement of the TiB2 → TiB transformation occurred producing more TiB whiskers in the hybrid composites. All samples of the hybrid composites exhibited improved yield strength (1365 MPa) and hardness (358 HV) compared to the non-hybrid ones 927 MPa and 254 HV, respectively. Graphical abstract

Influence of the Technology of Obtaining the Material of the Cathode of the Cu – Fe System at the Depth of Penetration of Ions into the Titanium Target

The article presents the results of the influence of the technology of obtaining the material of the cathode of the implanter of the Cu – Fe system on the penetration depth of the titanium alloy VT20. It is shown that the use of 50% Cu – 50% Fe material as the material of the cathode of the implanter, obtained by alloying copper and iron, leads to a better increase in the thickness of the ion-doped layer than the use of the cathode obtained by powder metallurgy.

Alternative Liquid Assisted-Sintering of AL/CU Composites Using Selective Powders of AS-Cast Al-ZN Alloy

Al and its alloys constitute one of the most versatile, economical and attractive materials for a wide range of applications. The 7xxx and 2xxx series alloys are those of achieving the highest mechanical strength among aluminum alloys. In this investigation, using powder metallurgy provides the microstructural and mechanical properties characterizations of non-commercial Al6Cu5Zn alloy by using powder metallurgy. Initial powder sizes are determined and the best condition is obtained for the distribution comprised between 75-106 μm. The samples are sintered at 585 oC, 600 oC and 615 oC during 0.5, 1.5 h and 3 h. It is found that mechanical behavior similar to as-cast Al-Cu based alloys is attained (~ 125 MPa) when the samples at 615 oC during 3 h are sintered. Considering the reduction of energy consumption and metal fumes commonly produced in foundry, Al-Zn powder can be used with Al and Cu elemental powders to constitute an Al6Cu5Zn alloy.