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激光立体成形TC4-TA19功能梯度材料的热行为和组织
Thermal Behavior and Microstructure of TC4-TA19 Functionally Graded Materials by Laser Solid Forming
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- DOI:
- 作者:
- 陈昱光 1,2,谭华 1,2,范 伟 1,2,米泽森 1,2,林 鑫 1,2,黄卫东 1,2
CHEN Yuguang1,2, TAN Hua1,2, FAN Wei1,2, MI Zesen1,2, LIN Xin1,2, HUANG Weidong1,2
- 作者单位:
- 1. 西北工业大学 凝固技术国家重点实验室,陕西 西安 710072;2. 西北工业大学 高性能金属增材制造工信部重点实验 室,陕西 西安 710072
1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China; 2. MIIT Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design, Northwestern Polytechnical University, Xi'an 710072, China
- 关键词:
- 功能梯度材料;激光立体成形;温度场;冷却速率;微观组织
functionally graded materials; laser solid forming; thermal field; cooling rate; microstructure
- 摘要:
- TC4-TA19 功能梯度材料可在同一结构不同部位获得不同的性能,具备工程应用潜力和价值。 激光立体成形是一种可靠的高性能金属构件制备技术,适用于制造功能梯度材料。 本文对激光立体成形 TC4-TA19 功能梯度材料的成形过程热行为和 3 种典型成分梯度区的组织形态进行了模拟和实验研究。 结果表明,成形温度场和凝固冷却速度受激光功率和层厚的影响显著,受扫描速度影响相对较小,对成分梯度不敏感。成分梯度区组织均由外延生长 β 柱状晶和晶内交错的 α 板条组成,其中 α 板条尺寸主要受合金成分影响,随 TC4 比例提高不断粗化。 成分梯度区中成分界面处的组织具有较高的连续性,成分梯度越小,界面越不明显。 成分梯度区具有较高的设计自由度,可通过调控激光功率和层厚优化凝固组织,利于实际生产。TC4-TA19 functionally graded materials can obtain different properties in different parts of the same structure, which has potential and value for engineering application. Laser solid forming is a reliable technique for fabricating high performance metal components, which is very suitable for fabricating functionally graded materials. The thermal behavior of TC4-TA19 functionally graded materials during laser solid forming and the microstructure morphology of three typical component gradient regions have been simulated and experimentally studied. The results show that the forming thermal field and solidification cooling rate are significantly affected by laser power and layer thickness, but less affected by scanning speed, and are not sensitive to component gradient. The microstructure in the composition gradient region is composed of β columnar crystals grown by epitaxial growth and α lath interlaced within the crystals. The α lath size is mainly affected by the composition of the alloy, and coarser with the increase of TC4 ratio. In the composition gradient region, the microstructure at the interface exhibit a high continuity, and the smaller the composition gradient, the less obvious the interface. The composition gradient zone has high design freedom and can optimize the solidification structure by adjusting laser power and layer thickness, which is beneficial to practical production.