Numerical simulation for temperature field of TC4 titanium alloy hollow blade during laser rapid forming process

The finite-element model of transient temperature field for hollow blade during laser rapid forming (LRF) process was developed. The transient temperature field evolution during laser rapid forming (LRF) process for TC4 alloy hollow blade was simulated by adopting the birth and death technology and the enthalpy potential method. The results show that the cooling rate and temperature gradient of melting pool are high about -1735°C/s and 8.34 × 10⁵°C/m, respectively, in the early stage for first layer melting pool. With increasing the deposited height of blade, the cooling rate and temperature gradient of melting pool become lower gradually. When the melting pool is about three quarter-height of the blade, the cooling rate is about -438°C/s and the temperature gradient is about 3.67 × 10⁵°C/m. At last, when the process of laser rapid forming is finished, the temperature distribution in hollow blade is from low (30°C at bottom of substrate) to high (1542°C at top of blade) along the vertical (Z axis) direction, the temperature gradient in substrate is smaller (about 5 × 10³°C/m) than that of in the blade (about 2.6 × 10⁴°C/m), and the main thermal transpiration direction is from top to bottom, and from melting pool to substrate.