Solid particle erosion response of aluminum reinforced with tungsten carbide nanoparticles and aluminide particles

The main concept behind this work is to further enhance the attractive properties of aluminum by fabricating Al - WC composites and evaluating them in terms of their solid particle erosion response. Aluminum Matrix Composites (AMCs) were produced by the addition of submicron sized WC particles (up to 2.5vol %) into a melt of Al1050. Casting was assisted by the use of K2TiF6 as a wetting agent and mechanical stirring in order to minimize particle clustering. Extensive presence of in-situ intermetallic phases (Al4W, Al5W, Al12W, Al3(Ti,W), Al3Ti) was observed in the cast products. Particle distribution was reasonably uniform comprising both clusters and isolated particles. Solid particle erosion experiments were carried out for impact angles of 30°, 60° and 90°, using angular Al2O3 particles as the eroding medium and under 5 bar spraying pressure. The erosion rate was calculated by measuring the mass loss and the eroded surfaces were examined with SEM-EDX. Increased erosion resistance was observed for low particle additions (≤ 1.0 vol%WC). Finally, a possible erosion mechanism was proposed based on the material’s microstructural and morphological characteristics

Solid particle erosion response of aluminum reinforced with tungsten carbide nanoparticles and aluminide particles

The main concept behind this work is to further enhance the attractive properties of aluminum by fabricating Al - WC composites and evaluating them in terms of their solid particle erosion response. Aluminum Matrix Composites (AMCs) were produced by the addition of submicron sized WC particles (up to 2.5vol %) into a melt of Al1050. Casting was assisted by the use of K2TiF6 as a wetting agent and mechanical stirring in order to minimize particle clustering. Extensive presence of in-situ intermetallic phases (Al4W, Al5W, Al12W, Al3(Ti,W), Al3Ti) was observed in the cast products. Particle distribution was reasonably uniform comprising both clusters and isolated particles. Solid particle erosion experiments were carried out for impact angles of 30°, 60° and 90°, using angular Al2O3 particles as the eroding medium and under 5 bar spraying pressure. The erosion rate was calculated by measuring the mass loss and the eroded surfaces were examined with SEM-EDX. Increased erosion resistance was observed for low particle additions (≤ 1.0 vol%WC). Finally, a possible erosion mechanism was proposed based on the material’s microstructural and morphological characteristics

NiAl-Cr-Mo Medium Entropy Alloys: Microstructural Verification, Solidification Considerations, and Sliding Wear Response

A series of NiAl-Cr-Mo systems were produced and assessed as far as their microstructure and their sliding wear resistance is concerned. The NiAl content was kept constant and seven compositions of Cr-Mo were tested, namely, 40Cr-0Mo, 30Cr-10Mo, 25Cr-15Mo, 20Cr-20Mo, 15Cr-25Mo, 10Cr-30Mo, and 0Cr-40Mo. It was observed that most of the systems contained primary phases, eutectic microconstituents, and, occasionally, intermetallic phases as the outcome of peritectic reactions. The extent and the nature of all these microstructural features was proved to be affected by the Cr/Mo relative ratio, and an attempt was conducted in order to explain the microstructural features based on solidification and other related phenomena. It was observed that the increase of the relative Mo/Cr ratio led to a significant restriction/elimination of the eutectic microconstituent. The sliding wear response of the produced system seems to diverge from the classical sliding wear laws of Archard and is based on multiple factors such as the nature of the oxide phases being formed upon sliding, the nature and the extend of the intermetallic phases being formed upon solidification, and the integrity and rigidity of the primary phases—last to solidify areas interfacial region and the factors that may influence this integrity

Al-RHEA Particulates MMCs by PM Route: Mechanical Properties and Sliding Wear Response

New particle reinforced aluminum matrix composites with the addition of refractory High Entropy Alloy, MoTaNbVW, fabricated via powder metallurgy process were assessed for their properties. Basic mechanical properties (modulus of elasticity, hardness) for the aluminum matrix, the pure aluminum and the reinforcement phase were assessed by means of dynamic nano-indentation technique. Nano-indentation based creep response was also evaluated in these three areas of interest. Hardness shows an increase with the addition of the particulates and so does the elastic moduli and the ratio of the energy absorbed in the elastic region. The creep response was approached in terms of dislocation mobility and critical volume for their nucleation. The produced Al–HEA composites were also studied for their sliding wear behavior and showed that with the increase in percentage of RHEA particulates the wear resistance increases. Microstructural considerations, wear track morphologies, and debris characteristics were used for the assessment of the involved wear mechanisms

Al-RHEA Particulates MMCs by PM Route: Mechanical Properties and Sliding Wear Response

New particle reinforced aluminum matrix composites with the addition of refractory High Entropy Alloy, MoTaNbVW, fabricated via powder metallurgy process were assessed for their properties. Basic mechanical properties (modulus of elasticity, hardness) for the aluminum matrix, the pure aluminum and the reinforcement phase were assessed by means of dynamic nano-indentation technique. Nano-indentation based creep response was also evaluated in these three areas of interest. Hardness shows an increase with the addition of the particulates and so does the elastic moduli and the ratio of the energy absorbed in the elastic region. The creep response was approached in terms of dislocation mobility and critical volume for their nucleation. The produced Al–HEA composites were also studied for their sliding wear behavior and showed that with the increase in percentage of RHEA particulates the wear resistance increases. Microstructural considerations, wear track morphologies, and debris characteristics were used for the assessment of the involved wear mechanisms

Microstructure and surface degradation of Al reinforced by Al

In the present effort, Al-AlxW composites have been prepared by vacuum arc melting (VAM), conventional casting (CAST) and free sintering (PM) with the objective to determine an effective fabrication route in terms of low cost, ease of manufacture and property boosting. The produced Aluminium Matrix Composites (AMCs) contain several types of in-situ aluminides. Their morphology, stoichiometry and distribution strongly depend on the fabrication route. The particulate aluminide reinforcements have a beneficial effect on the wear response of the monolithic matrix. VAM-AMCs show the highest resistance to wear. A wear mechanism is proposed

The Advanced Assessment of Nanoindentation-Based Mechanical Properties of a Refractory MoTaNbWV High-Entropy Alloy: Metallurgical Considerations and Extensive Variable Correlation Analysis

In the present study, a thorough examination of nanoindentation-based mechanical properties of a refractory MoTaNbVW high-entropy alloy (RHEA) was conducted. Basic mechanical properties, such as the indentation modulus of elasticity, indentation hardness, and indentation-absorbed elastic energy, were assessed by means of different input testing variables, such as the loading speed and indentation depth. The obtained results were discussed in terms of the elasto-plastic behavior of the affected material by the indentation process and material volume. Detailed analysis of the RHEA alloy’s nanoindentation creep behavior was also assessed. The effect of testing parameters such as preset indentation depth, loading speed, and holding—at the creep stage—time were selected for their impact. The results were explained in terms of the availability of mobile dislocations to accommodate creep deformation. Crucial parameters, such as maximum shear stress developed during testing (τmax), critical volume for dislocation nucleation (Vcr), and creep deformation stress exponent n, were taken into consideration to explain the observed behavior. Additionally, in all cases of mechanical property examination and in order to identify those input testing parameters—in case—that have the most severe effect, an extensive statistical analysis was conducted using four different methods, namely ANOVA, correlation matrix analysis, Random Forest analysis, and Partial Dependence Plots. It was observed that in most of the cases, the statistical treatment of the obtained testing data was in agreement with the microstructural and metallurgical observations and postulates