Particle Erosion Induced Phase Transformation of Different Matrix Microstructures of Powder Bed Fusion Ti-6Al-4V Alloy Flakes

Abstract

In this study, powder bed fusion Ti-6Al-4V alloy flake was subjected to heat treatment at 800 °C for 4 h for inducing the complete transformation of the α’ phase into the α+β phases. An erosion experiment with 450 µm mean particle diameter of Al2O3 particles at a 90° impact on both the as- powder bed fusion (PBF) Ti-6Al-4V and the 4-h 800 °C heat-treated specimens to clarify the particle erosion-induced phase transformation behavior and its effect on mechanical properties. Particle erosion-induced phase transformation to the α phase was observed on both the as-PBF Ti-6Al-4V and the heat-treated specimens. It brought about a sequential formation from the surface to the bottom: (1) a surface softened zone, (2) a hardened zone, and (3) a hardness stabilization zone. The as-PBF Ti-6Al-4V was positively eroded by erosion particles, decreasing strength and ductility. In the case of the heat-treated specimens, we found decreased strength yet an increased ductility.

Al2O3 Particle Erosion Induced Phase Transformation: Structure, Mechanical Property, and Impact Toughness of an SLM Al-10Si-Mg Alloy

“…According to studies in the literature [ 30 , 31 , 32 ], when a ductile metal material is hit with erodent particles, the peak erosion rate appears at the impingement angles of 15°–30°. The erosion rates of the F and FH groups of specimens as functions of the impingement angle are illustrated in Figure 11 .…”

“…In particle erosion, the ceramic particles hit the surface of the metal specimens at high speed, and their kinetic energy is converted into heat energy, which can generate temperatures of 400–500 °C instantaneously [ 22 , 23 , 31 ] and cause surface oxidation to form Al 2 O 3 . As depicted in Figure 14 a,b, the F group of specimens transformed into the FE group of specimens after erosion.…”

Erosion Resistance and Particle Erosion-Induced Tensile Embrittlement of 3D-Selective Laser Melting Inconel 718 Superalloy

“…After the positive erosion, the stress-strain curves of the four specimens shifted to the right slide, the ductility also reduced significantly. According to previous studies [15][16][17][18], temperature increase on the impacted specimen surface induces phase transformation. Wood [17] and Zhao [18] described that erosion would lead to high temperature, making the phase dissolve and the surface layer soft.…”

“…Table 1 shows the SLM process parameters used in this study. The raw material IN718 powder supplied by EOS GmbH (Electro-Optical Systems, Krailling, Germany) had an average particle size of 15 µm ( printed Ti-6Al-4V [18]. The heat generated by particle impact or strain helps dissolve a phase or form a new phase, further affecting the hardness and other mechanical properties.…”

“…We are interested in particle erosion resistance and the erosion induced phase transformation of 3D-printed IN718.Particle erosion wear could induce phase transformation. This phenomenon has been confirmed by Al-Si-Mg alloy [15], austempered ductile iron (ADI) [16], 316 stainless steel [17], and even 3D-printed Ti-6Al-4V [18]. The heat generated by particle impact or strain helps dissolve a phase or form a new phase, further affecting the hardness and other mechanical properties.Based on this, the purpose of this study is to investigate the microstructure and the mechanical properties of heat-treated SLM Inconel 718.…”