Microstructures and properties of high-entropy alloys

Get the phase diagram information you need at a price you can afford. Key Features: Peer reviewed by the Japanese Committee for Alloy Phase Diagrams. Updated through April 2000. Total number of diagrams = 2,332 (605 are new of greatly revised diagrams; among these 171 are not in Binary Alloy Phase Diagrams, 2nd Edition). Approximately 600 crystal structure tables of systems for which phase diagrams are unknown. You've been asking for a simple book containing just binary phase diagrams and crystal structure data. Desk Handbook: Phase Diagrams for Binary Alloys meets this need, and it presents the most current information. Updates the previous print compilation of binary phase diagrams by 10 years. Presents diagrams in consistent size. Shows the principal axis in atomic per cent, with a secondary axis in weight per cent. Includes an introductory article on phase diagrams and their use. Gives reference to the original literature source. This volume is the latest outgrowth of the phase diagram activity in which ASM International has been involved since 1978.

Desk handbook phase diagrams for binary alloys

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Selective laser melting (SLM) and laser cladding deposition (LCD) are two typical kinds of laser additive manufacturing techniques that have been developed for many years independently. Although they are based on the same principle of laser cladding, there are little comparison on the fundamental studies for metallurgical behavior (including melting and solidification behaviors) and the mechanical properties of these two techniques up to now. In this paper, the single-track formation and the deposition of block sample from 316L stainless steel powders have been carried out by both SLM and LCD techniques. A comparison on pool shape, cooling rate, columnar grain size and mechanical properties under different processing conditions by LCD and SLM respectively has been studied. It is found that, due to the increase of energy input and the decrease of depth-to-width ratio of melting pool (MP) from SLM to LCD, the primary cellular arm spacing (PCAS) of the sample increases from less than 1.0 µm to more than 15.0 µm, and thus the cooling rate of MP decreases from about 106 K/s in SLM to about 102 K/s in LCD. Furthermore, due to the decrease of cooling rate from SLM to LCD, the columnar grains of the as forming alloy are getting coarser. Especially, the relationship between gain size (λ) and the reciprocal of square root of cooling rate ( T ) in LCD significantly meets the classical linear function of λ = a + b / T (a and b are constants), while a new relationship of a cubic function is found in SLM, showing the different solidification characteristics between LCD and SLM. Lastly, the samples of 316L stainless steel by SLM have much stronger tensile strength but lower elongation than those by LCD, and the main reason is due to that the solidification behavior of the MPs by SLM can form much finer columnar grains than those by LCD.

A comparison on metallurgical behaviors of 316L stainless steel by selective laser melting and laser cladding deposition

Review of metal matrix composites with high thermal conductivity for thermal management applications

Effects of TiC content and size on the microstructure, density, hardness and wear resistance of Al–4 wt.% Cu matrix composites were investigated. Al–4 wt.% Cu matrix composites were fabricated using two main processing routes of powder metallurgy (PM) and casting. In the PM process, Al–4 wt.% Cu matrix alloy reinforced with 10 wt.% TiC particulates of two different average sizes (13 μm and 93 μm) were mechanically alloyed and sintered. In the second process, Al–4 wt.% Cu– x TiC ( x  = 5, 10, 15 and 20 vol.%) composites were fabricated using a flux-assisted casting. Both the wear resistance and the hardness of cast composites improved with TiC content. The sintered composite containing smaller TiC particles (0.6–3.5 μm) exhibited higher hardness than that reinforced with coarser TiC (0.8–5.6 μm) particles. However, the detachment of carbide particles from wear surfaces of the composite reinforced with TiC particles (0.6–3.5 μm) results in the deterioration of its wear resistance.

Comparative processing-structure-property studies of Al-Cu matrix composites reinforced with TiC particulates

The present study reinvestigates the Al-Ce and Al-Nd phase diagrams and reoptimizes their thermodynamics using the CALPHAD method. First-principles energy calculations play an important role in terms of sublattice formalism and phase-stability prediction, demonstrating that they should be effectively integrated into experimental investigations and thermodynamic assessments. Specifically, current experimental results and theoretical calculations show that Al2Nd (or Al2Ce) should be treated as a stoichiometric compound phase rather than as the solution phase that was proposed in previous studies. Further, a new compound, AlCe2, is found stable at high temperatures (648 °C to 775 °C) in the Al-Ce system. It forms through a peritectic reaction of liquid and AlCe phases at 775 °C, and decomposes into AlCe and βAlCe3 at 648 °C and below. Since the AlCe2 phase is not retained at room temperature by quenching experiments, it is suggested that AlCe2 may be isostructural with the previously known compound AlNd2 (oP12). Based on current differential thermal analysis (DTA) measurements and theoretical calculations, it is also proposed that there is an α/βAl3Ce polymorphous transition occurring at 973 °C in the Al-Ce system and an α/βAl3Nd polymorphous transition occurring at 888 °C in the Al-Nd system. The βAl3RE phase may be isostructural with βAl3Y (hP12). Finally, the previously described βAl11RE3 phase (rare earth elements (RE)=La, Ce, Nd, or Pr) is proposed to have a stoichiometry of Al4RE (tI10), based on direct evidence from differential scanning calorimetry (DSC) measurements.

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Reassessment of Al-Ce and Al-Nd binary systems supported by critical experiments and first-principles energy calculations

The effect of heat input from laser beam welding (LBW) on the microstructural evolution of superalloy Inconel 718 was investigated. LBW was carried out on 1.6-mm-thick sheets with an average grain size of 13 μm (ASTM # 9.5), and four different heat inputs in the range of 74.5 mm−1 to 126.6 J mm−1 were used. Full penetration was achieved in all weld experiments. Microstructures of the welds were evaluated using an optical microscope and a field emission scanning electron microscope. Increasing the heat input changed the resulting weld shape from a wine glass shape to a stemless glass shape with wider surface bead widths, and the measured average dendrite arm spacing was increased from 1.06 μm to 2.30 μm, indicating the corresponding solidification rate in the range of 1.75 × 105 K s−1 (°C s−1) to 3.5 × 106 K s−1 (°C s−1). The welds also were free from microfissuring even at the lowest heat input trials. The Nb concentration of Laves phase for the current LBW samples was ≈20.0 wt pct. The coefficients of partition and distribution for Nb were determined to be approximately 3.40 and 0.50, respectively.

A Study on Laser Beam Welding (LBW) Technique: Effect of Heat Input on the Microstructural Evolution of Superalloy Inconel 718

The effect of plastic deformation on the microstructural evolution of an Al-5.0Cu-0.5Mg (wt pct) ternary alloy was investigated. Hardness measurements and quantitative precipitate analysis were performed on specimens that were water quenched from a solution heat treatment, stretched either 0 or 6 pct and immediately aged at ambient temperature or artificially aged at 200 °C or 250 °C for times up to 3000 hours. Quantitative transmission electron microscopy (TEM) was used to characterize Ω and θ′ number density, diameter, and thickness as a function of preage mechanical stretch and artificial aging condition. Age hardening curves for naturally and artificially aged specimens revealed an increase in hardness corresponding with a preage stretch. Quantitative TEM verified an increase in the number density and a refinement of precipitates for both Ω and θ′ between the 0 and 6 pct stretch condition for those samples artificially aged. When aged at 200 °C, θ′ exhibited superior coarsening resistance relative to the Ω phase. The quantified Ω coarsening kinetics were greater than similar Ag-containing alloys. To investigate the effects of trace Si additions on subsequent microstructural evolution, a series of Al-Cu-Mg-Si quaternary alloys were produced. The addition of 0.1Si (wt pct) was found to suppress Ω precipitation in most Al-4.0Cu-xMg alloys investigated. These initial results indicate that Ω precipitation may be related to the Mg/Si ratio.

The effect of cold work on the precipitation of Ω and θ′ in a ternary Al-Cu-Mg alloy

Dross is an unavoidable by-product of the aluminum production. It forms at the surface of the molten metal as the latter reacts with the furnace atmosphere. Depending on the process, it contains, on average, about 50% free aluminum metal dispersed in an oxide layer. Since the aluminum production is highly energy-intensive, dross recycling is very attractive from both the energy and the economic standpoints. The conventional recycling process using salt rotary furnaces is thermally inefficient and environmentally non-acceptable because of the production of salt slags. Several salt-free dross treatment processes have been proposed in the last few years, their operation, energy consumption and metal yield will be described in detail and compared in the present paper.

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Papers

Comparative processing-structure-property studies of Al-Cu matrix composites reinforced with TiC particulates

Reassessment of Al-Ce and Al-Nd binary systems supported by critical experiments and first-principles energy calculations

A Study on Laser Beam Welding (LBW) Technique: Effect of Heat Input on the Microstructural Evolution of Superalloy Inconel 718

The effect of cold work on the precipitation of Ω and θ′ in a ternary Al-Cu-Mg alloy

Comparison of salt-free aluminum dross treatment processes