研究目的
To develop and implement a novel inductive high temperature Laser Powder Bed Fusion system capable of processing Ti-48Al-2Cr-2Nb without cracking, achieving high density parts with controlled cooling rates.
研究成果
The novel HT-LPBF system successfully processed Ti-48Al-2Cr-2Nb without cracking, achieving apparent densities in excess of 99%. The inductive preheating system maintained a stable powder bed temperature of 800 °C and controlled cooling rates, which were critical for suppressing crack formation. This work demonstrates the potential of high-temperature preheating in LPBF for processing difficult-to-weld alloys, offering a pathway to combine the geometric precision of LPBF with the material versatility of EBM.
研究不足
The study was limited by the prototypal nature of the HT-LPBF system, which may not yet match the scalability and robustness of industrial systems. The control logic for temperature regulation was simple (ON/OFF), leading to temperature fluctuations, especially at lower temperatures. Future work could explore more sophisticated control algorithms and the system's applicability to other crack-susceptible alloys.
1:Experimental Design and Method Selection:
The study involved the design and testing of a novel inductive preheating system integrated into a Laser Powder Bed Fusion (LPBF) setup. The system was designed to achieve high preheating temperatures (up to 800 °C) and controlled cooling rates (5 °C/min) to prevent cracking in γ-TiAl alloys.
2:Sample Selection and Data Sources:
Ti-48Al-2Cr-2Nb powder was used as the feedstock material. The powder's chemical composition and size distribution were provided by the producer.
3:List of Experimental Equipment and Materials:
The setup included a custom LPBF system with an inductive preheating coil, a 1000 W single-mode fiber laser, and a controlled atmosphere chamber. Materials included Ti-48Al-2Cr-2Nb powder and Ti6Al4V substrate.
4:Experimental Procedures and Operational Workflow:
Specimens were built with and without preheating. The preheating system was tested at various temperatures, and the cooling rate was controlled post-deposition. The process was monitored using a K-type thermocouple.
5:Data Analysis Methods:
The specimens were characterized for crack density, apparent density, and microhardness. Optical microscopy and scanning electron microscopy were used for microstructural analysis.
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