Effect of Nickel Alloying and Mechanical Stirring on the Microstructure and Mechanical Properties of Al – 10% Si – 5% Cu Alloy

Metal Science and Heat Treatment - The effect of nickel additions on the microstructure and ultimate tensile strength of alloy Al – 10% Si – 5% Cu in cast and heat treated conditions is...     

Effect of Phase Composition on the Resistance of Hydrogen-Charged Ti – 6% Al Alloy to Compressive Strain

Effect of hydrogen (0.004 – 1.0%) on the ductility and strain resistance of titanium alloy Ti – 6% Al in a temperature range of 400 – 1050°C at a deformation rate of 5 × 10^{– 3}, 5 × 10^{– 2}, and 5 × 10^{– 1} sec^{– 1} is studied. The relation between the quantitative and qualitative phase compositions forming in the alloy as a result of its alloying with hydrogen and the main parameters of the deformation process are determined. Hardening and softening of the alloy in the single-phase - and -ranges and the double-phase ( + )-range are investigated. The temperature range of maximum ductility of hydrogen-charged alloy Ti – 6% Al is determined.     

Effect of Annealing Temperature on the Microstructure and Mechanical Properties of Selective Laser Melted Alloy Ti – 6% Al – 4% V

Metal Science and Heat Treatment - The effect of annealing at 700, 800, 900 and 1000°C on the microstructure and mechanical properties of alloy Ti – 6% Al – 4% V obtained by...     

Effect of Scandium Content on the Structure and Properties of Alloy Al – 4.5% Zn – 4.5% Mg – 1% Cu – 0.12% Zr

Metal Science and Heat Treatment - The effect of scandium content on the structure and properties of alloy Al – 4.5% Zn – 4.5% Mg – 1% Cu – 0.12% Zr is determined. The...     

Effect of Al_4C_3 Particle Size Distribution in a Al–2.5C Master Alloy on the Refining Efficiency of the AZ31 Alloy

The Al–2.5C master alloy is prepared to investigate the effect of the Al_4C_3 particle size distribution on the refining efficiency of the AZ31 alloy. The results indicate that the Al_4C_3 particles are potent nucleation substrates for primary a-Mg grains. With 1.0 wt% master alloy addition, the grain size is reduced from 204 to 70 lm. The grain refining efficiency of the Al_4C_3 particles on the AZ31 alloy is calculated to be 0.04%–0.75%. Such low refining efficiency is mainly attributed to the size distribution of the Al_4C_3 particles. The particle sizes are in the range from 0.18 to 7.08 lm, and their distribution is well fitted by a log-normal function. The optimum particle size range for significant grain refinement is proposed to be around 5.0–7.08 lm in the present conditions.     

Effect of Radial Shear Rolling on the Structure and Mechanical Properties of a New-Generation High-Strength Aluminum Alloy Based on the Al – Zn – Mg – Ni – Fe System

Metal Science and Heat Treatment - A high-strength aluminum alloy based on the Al – Zn – Mg – Ni – Fe system is studied in deformed condition after radial shear rolling with...     

Effect of B and Ti on the directionally solidified microstructure of the Nb–Si alloys

With the guidance of the calculated phase diagram of the Nb–Ti–Si–B system, three alloys (M1: Nb–20Ti–14Si; M2: Nb–20Ti–14Si–4.5B; M3: Nb–24Ti–14Si–4.5B (at.%)) were selected to investigate the influence of alloying elements B and Ti on their microstructural formation. The alloys were prepared by arc-melting and then directionally solidified (DS) at a withdrawing rate of 10 μm/s. The DS microstructures in the near-solidification front zone, the mushy zone, and the steady-state zone were characterized by SEM, EPMA and XRD analyses. The experimentally observed solidified microstructures were then compared with the predicted solidification path calculated from the Scheil model. The good agreement between the experimental observations and the predicted solidification paths suggests that the computational models can be effectively used for the design of the Nb–Ti–Si–B alloys.     

The Influence of the Alloy Microstructure on the Oxidation Behavior of Ti–46Al–1Cr–0.2Si Alloy

The influence of microstructure of the two-phase alloyTi–46Al–1Cr–0.2Si on the oxidation behavior in air between600 and 900°C was studied. The oxidation rate, type of scale, and scalespallation resistance were strongly affected by the type of microstructure,i.e., lamellar in as-cast material and duplex after extrusion at1300°C. The oxidation rate was affected by the size and distribution ofthe ₂-Ti₃Al phase, being faster for the extrudedmaterial with coarse ₂-Ti₃Al. The type of oxide scaledetermines the spalling resistance. Cast material developed a uniform scalethat spalled off after short exposure times at 800 and 900°C when a criticalthickness was reached. The extruded material presented a heterogeneous scalewith predominant thick regions formed on -TiAl-₂-Ti₃Algrains and thin scale regions formed on -TiAl grains. Thistype of scale could permit an easier relaxation in the matrix of stressesgenerated by both thermal-expansion mismatch between scale and alloy andoxide growth, resulting in a higher spallation resistance.