Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 14, 2021 - November 18, 2021
Laser metal wire deposition (LMwD) has become an alternative AM method for Ti6Al4V alloy forming while some difficulties still exist, which could be classified as parts distortion, oxidation and uncontrollable mechanical properties of as-built samples. In the present work, the printer with a coaxial laser supplied by two laser irradiation heads was carried out to investigate the microstructure mainly of as-built one bead samples. The results showed that: Under the optical microscope and scanning electron microscope (SEM), and the coarse columnar β phase, typically acicular martensite α' phase and some pores were observed clearly. The size of α' decreases from deposition zone (DZ) to fusion zone (FZ). From FZ to heat-affected zone (HAZ), the α' gradually transferred into epitaxial grains and the pores increased. The forming of pores may result from incomplete heat input or inadequate shielding gas input. Besides, the SIMUFACT software was used to simulate the temperature and residual stress distribution of substrate simultaneously. The results showed that the growth direction of β grains is essentially in agreement with the direction of the maximum temperature. The residual stress distribution of substrate after printing was discussed as well.
