Understanding Solidification in Metal Additive Manufacturing — Lesson 3

This lesson covers the intricate process of solidification in metal additive manufacturing. It delves into the equilibrium and non-equilibrium phases of solidification, the theory and mechanism behind it, and the appearance of raw metal additive manufacturing printed parts. The lesson also explores the role of cooling in the solidification process, the thermodynamics of solid and liquid states, and the impact of heat transfer. It further discusses the effects of rapid solidification, the role of thermal conductivity, and the influence of laser and electron beam in additive manufacturing. The lesson concludes with an examination of the cooling curve and phase diagram for steel and the challenges in drawing a CCT diagram for additive manufactured parts.

Video Highlights

01:10 - Explanation of the process of solidification in metal, including the role of cooling and heat transfer, and the importance of understanding the energy of solid and liquid at the melting point
04:28 - Discussion on the use of molecular dynamic simulation tools in understanding solidification at micro, meso, and macro levels in additive manufacturing
12:26 - Discussion on the impact of thermal conductivity on solidification and the differences in the solidification process in different metals like titanium and copper
23:46 - Discussion on the impact of cooling rate on the formation of different phases in alloys during solidification
41:16 - Explanation of the process of solidification in additive manufacturing using a cooling curve and phase diagram, highlighting the differences from standard casting methods

Key Takeaways

- Solidification in metal additive manufacturing involves equilibrium and non-equilibrium phases.
- Cooling plays a crucial role in the solidification process, initiating the transformation from liquid to solid.
- Thermodynamics play a significant role in the solidification process, with solid and liquid having the same energy at their melting point.
- Rapid solidification can lead to the formation of metastable phases and unique structures.
- The cooling curve and phase diagram provide insights into the solidification process, though drawing a CCT diagram for additive manufactured parts presents challenges.