| dc.description.abstract | The alloy composition of Fe-Cr-Mo-C-B-Co-Al 7 components Fe-based alloy was selected as the master alloy and prepared by vacuum induction melting. Then the alloy ingots were re-melted and fabricated into spherical
alloy powder by gas atomization process. There are two sources of powder in this study, from the Material and Chemical Laboratories, Industrial Technology Research Institute (ITRI, Hsinchu) and Chung Yo Materials Co.,Ltd.(C.Y.M, Kaohsiung). After size sieving, the Fe-based alloy powder was characterized its amorphous status by X-ray diffraction (XRD). The XRD results revealed that a broaden peak accompanied the weak crystalline peaks of α-Fe occurred at the alloy powders with particle size below 90μm. Meanwhile, the appearance of all these Fe-based alloy powders present a spherical shape and a solid cross-section.In order to improve the fluidity of the powder to facilitate powder spreading, removing the powder below 25 μm by Cyclone screening in C.Y.M and use this powder and another powder which hasn’t been sieved by cyclone
to do additive manufacture by selective laser melting (SLM) with 60W-150mm/s parameters for property analysis. The analysis results showed that the hardness of the specimen made of cyclone screened powder was increased from 924 Hv to 1148 Hv, and the density increased from 7.22 g/cm3 to 7.51 g/cm3.In terms of corrosion resistance, the corrosion current and corrosion voltage are 7.40x10-7
(A/cm2) and -0.254V is better than SLM specimen without cyclone sieveing. It can be seen that the cyclone sieveing
improves the quality of the powder and improves the performance of the SLM specimen.
The powder which prepared by C.Y.M to make SLM specimen of 5 different energy densities, and tested their XRD, thermal properties, density,mechanical properties and corrosion resistance. It is found that as the energy
density decreases, the amorphous ratio and hardness of specimen will increase,but at the same time the density will also decrease. Therefore, the corrosion
resistance test is used to prove specimen which has the best performance. It is found that the corrosion resistance of Sample II (Overlapping 30%) is better
than the other four types of SLM specimen, which is the best parameter. | en_US |