Selective Laser Melting of Cu–10Sn–0.4P: Processing, Microstructure, Properties, and Brief Comparison with Additively Manufactured Cu–10Sn

Abstract

Cu and Cu alloys are important materials with extensive industrial applications in fields such as electronics, construction, and transportation. [1] Tin bronze (Cu-Sn) was one of the earliest alloys used by humans, [2,3] and offers outstanding wear and corrosion resistance. It is widely employed in the marine industry, [4,5] and as a bearing material. [6] Cu-Sn alloys are also used in electrical connectors and electronic components due to their good machinability. [7] Phosphorus (P) is commonly used as an alloying element in Cu-Sn alloys at doping levels of up to 0.5 wt%, and offers various beneficial effects at optimal concentrations. [8][9][10][11] Specifically, P doping can potentially lead to a lower stacking fault energy for an easier plastic deformation, [8] an enhanced wear resistance due to grain boundary phase formation to refine grain size, [9] an improved melt property due to lower viscosity, [10] and purified melt due to oxygen scavenging from the Cu matrix. [10,11] In contrast, Cu-Sn alloys with a Sn content above 5 wt% tend to generate a brittle δ phase within the microstructure, which lowers the plasticity. Thus, casting has become the most popular fabrication technique for high-Sn-Cu alloys (e.g., Cu-10Sn). [11] However, as-cast Cu-10Sn is prone to defects such as low densification, shrinkage cavities, microcracks, and severe segregation, thus advanced manufacturing processes are required. [12,13] Alternatively, recently developed laser-based additive manufacturing (AM) and 3D printing techniques can be used for the manufacturing of Cu-Sn alloys. They offer several advantages, including free-form fabrication without molds, friendly working environment, and short production cycles. [14][15][16] Many studies have investigated the production of high-quality parts from various materials using AM. However, Cu and Cu alloys are often regarded as highly reflective materials, particularly for near-infrared (NIR) laser beams, which can result in poor laser absorptivity. [17][18][19][20][21][22] Gu et al. [23] used selective laser sintering (SLS) to print Cu-10Sn and Cu-8.4 P components, whereas Mao et al. [13] used selective laser melting (SLM) to manufacture Cu-15Sn parts with a relative density of 99.6% at a laser power of 187 W, scanning speed of 185 mm s À1 , and 0.17 mm of hatch space. Furthermore, a bimetallic structure consisting of 316L stainless steel and Cu-10Sn was produced using SLM. [24,25] SLS and SLM are laser-based AM technologies, whereas selective electron beam melting (SEBM) uses an electron beam as the heat source to melt the feedstock powder to overcome the poor laser absorptivity of many Cu and Cu alloys. [26] However, SEBM normally has a lower forming accuracy and surface roughness than SLM. [14,15,26] Overall, currently SLM offers several advantages, but SLM-prepared Cu and Cu alloys (e.g., Cu-10Sn) can also

Intentional Oxidation and Laser Remelting of Highly Reflective Pure Cu for Its High‐Quality Additive Manufacturing

“…Laser printed metallic materials tend to show residual stress at different levels, which is confirmed to be a major contributing factor to the lower ductilities observed [33] . This finding applies to an SLM-prepared Cu-Sn alloy, too [23] . To adopt stress relief heat treatment can be a plausible approach to address this problem, which details can be explored in future studies.…”

“…The corresponding approaches include: (a) To use shorter wavelengths lasers (e.g. 488 nm blue laser) to increase absorptivity by pure Cu [16][17][18] ; (b) to utilize high energy input by using high laser power up to 1 kW [19,20] ; and (c) to introduce light absorbent such as TiC and carbon nanotube, or alloying to enhance absorptivity [21][22][23] . To optimize processing parameters may be also able to result in a high density although the processing window is often narrow [24][25][26] .…”

“…The corresponding approaches include 1) using shorter-wavelength lasers (e.g., 488 nm blue laser) to increase absorptivity by pure Cu; [16][17][18] 2) utilizing high-energy input using high laser power up to 1 kW; [19,20] and 3) introducing light absorbents such as TiC and carbon nanotubes or alloying to enhance absorptivity. [21][22][23] Optimizing processing parameters may be also able to result in high density although the processing window is often narrow. [24][25][26] However, considering the importance of pure Cu, more research efforts are required particularly regarding powder feed stock modification and processing optimization in terms of laser remelting.…”

Investigation of Microstructural, Mechanical and Corrosion Properties of Cu-10Sn Bronze Parts Produced by Selective Laser Melting

“…Compared to the Cu-10Sn alloys produced by the SLM technique in the literature, very high values were obtained. [2,8,21,22]. Comparison of SLM production parameters is given in Table 3.…”

Microstructural and Mechanical Properties of Polylactic Acid/Tin Bronze Tensile Strength Bars Additive Manufactured by Fused Deposition Modelling

“…Table 2 lists mechanical properties of CuSn10 as continuous cast, the most often occurring form at the market [5]. Ruinan et al [10] and Deng et al [11] investigate feasibility of SLM for component manufacture. They print TS-bars and perform tensile testing on them.…”