Adjei-Kyeremeh Frank, Pratesa Yudha, Shen Xiao, Song Wenwen, Raffeis Iris, Vroomen Uwe, Zander Daniela, Bührig-Polaczek Andreas
Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen, Germany.
Chair of Corrosion and Corrosion Protection, Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen, Germany.
Materials (Basel). 2023 Jul 10;16(14):4916. doi: 10.3390/ma16144916.
In this paper, the high strength and lightweight Al-Cu-Li alloy (AA2099) is considered in as-built and preheated conditions (440 °C, 460 °C, 480 °C, 500 °C, and 520 °C). The purpose of this study is to investigate the influence of laser powder bed fusion (LPBF) in situ preheating on precipitation microstructure, mechanical and corrosive properties of LPBF-printed AA2099 alloy compared to the conventionally processed and heat-treated (T83) alloy. It is shown that precipitations evolve with increasing preheating temperatures from predominantly globular Cu-rich phases at lower temperatures (as-built, 440 °C) to more plate and rod-like precipitates (460 °C, 480 °C, 500 °C and 520 °C). Attendant increase with increasing preheating temperatures are the amount of low melting Cu-rich phases and precipitation-free zones (PFZ). Hardness of preheated LPBF samples peaks at 480 °C (93.6 HV0.1), and declines afterwards, although inferior to the T83 alloy (168.6 HV0.1). Preheated sample (500 °C) shows superior elongation (14.1%) compared to the T83 (11.3%) but falls short in tensile and yield strength properties. Potentiodynamic polarization results also show that increasing preheating temperature increases the corrosion current density (Icorr) and corrosion rate. Indicated by the lower oxide resistance (R), the Cu-rich phases compromise the integrity of the oxide layer.
在本文中，研究对象是高强度、轻质的Al-Cu-Li合金（AA2099）的成型态以及预热状态（440℃、460℃、480℃、500℃和520℃）。本研究的目的是探究激光粉末床熔融（LPBF）原位预热对LPBF打印的AA2099合金的析出组织、力学性能和耐腐蚀性能的影响，并与传统加工和热处理（T83）合金进行比较。结果表明，随着预热温度的升高，析出相从低温时（成型态、440℃）主要为球状富铜相演变为更多的片状和棒状析出相（460℃、480℃、500℃和520℃）。随着预热温度的升高，低熔点富铜相和无析出区（PFZ）的数量也随之增加。预热后的LPBF样品硬度在480℃时达到峰值（93.6 HV0.1），之后下降，尽管低于T83合金（168.6 HV0.1）。预热样品（500℃）的伸长率（14.1%）优于T83合金（11.3%），但在拉伸强度和屈服强度性能方面有所不足。动电位极化结果还表明，预热温度升高会增加腐蚀电流密度（Icorr）和腐蚀速率。富铜相的抗氧化性较低（R），这表明其会破坏氧化层的完整性。
