Effect of Powder Size on Microstructure and Mechanical Properties of 2A12Al Compacts Fabricated by Hot Isostatic Pressing

Abstract

This paper studied the effects of powder size on densification, microstructure, and mechanical properties of the hot isostatic-pressed 2A12 aluminum alloy powder compact. The results show that the near-fully dense powder compact can be successfully achieved and the smaller the powder is, the higher the relative density is. In addition, as the powder size decreases, the precipitated phases in the powder compact change from continuously point-like distribution at the junctions among powder particles to the concentrated distribution at the three-way intersections. Compared with the large powder, the tensile strength, yield strength, and elongation of the compact with the small powder were improved by 14%, 30.8%, and 48.6%, respectively.

Rapidly Solidified Gas-Atomized Aluminum Alloys Compared with Conventionally Cast Counterparts: Implications for Cold Spray Materials Consolidation

“…To test the feasibility of the notion that (1) was responsible, one would expect the Mg content within the Al 6061 and Al 7075 castings to be overestimated, too. However, the fact that the wt.% of Mg within the cast Al 6061 sample was slightly lower than the specified lower limit of 0.8 wt.%, at 0.66 wt.%, detracts from the feasibility of explanation (1). The fact that the wt.% of Mg within the cast Al 7075 sample was within the defined range at 2.21 wt.% also detracts from (1) listed above as well.…”

“…From Figure 3c, one may note that the calculated cooling rates as a function of particle diameter for each of the gas-atomized systems considered during the course of this work were similar to one another. Figure 3c also enabled the visualization of consequences associated with the inverse proportionality between molten metal droplet diameter and cooling rate, which was mathematically expressed in Equation ( 2) upon inspection of the simplified heat transfer model for the rapidly solidified powders presented in Equation (1). A detailed consideration of Figure 3c also identified gas-atomized Al 6061 as the rapidly solidified alloy with the greatest cooling rate for a given particle size, followed by Al 7075 and Al 2024, in that order.…”

“…As such, a relatively simple Newtonian heat transfer model, which was reported by Shiwen et al [22], was found to be adequate in capturing the mechanisms behind single particle solidification during gas atomization. The simplified heat transfer model for rapidly solidified powders is given in Equation (1), such that…”

“…The production of metallic powders has traditionally been of interest to classical powder metallurgists and research and development engineers alike. Powder metallurgy techniques include hot isostatic pressing, injection molding, and powder forging, among others [1][2][3]. However, the advent and realization of metal additive manufacturing's potential has enabled a renaissance within the powder production, powder metallurgy, and alloyed powder design communities.…”

“…Computational tools can greatly decrease the time required to fully understand cold-spray material consolidation processing and manufacturing, thus decreasing the number of experiments needed to better comprehend the influence of parameters and properties of interest. Accordingly, models have been developed to (1) utilize commercially available thermodynamic and kinetic software, such as Thermo-Calc and Thermo-Calc's DICTRA module (Thermo-Calc Software, Stockholm, Sweden), which uses the chemical composition of the feedstock material, and then (2) couples the outputs associated with (1) with the cold spray consolidation process parameters, such that (3) the output material properties of a consolidated part/component may be derived [14]. The process of integrating feedstock composition with processing parameters and the resultant component performance, by way of taking an in silico approach, has previously been described within the literature as a through-process modeling approach to cold spray materials consolidation and cold spray metal additive manufacturing.…”