Influence of phosphorus element on direct laser sintering of multicomponent Cu-based metal powder
- PDF / 726,917 Bytes
- 11 Pages / 612 x 792 pts (letter) Page_size
- 57 Downloads / 242 Views
ODUCTION
DIRECT metal laser sintering (DMLS) is a laser-based rapid manufacturing process that enables the quick production of complex shaped three-dimensional (3-D) parts directly from metal powder.[1–4] As compared with indirect laser sintering or other conventional processes, the main advantages associated with this technique are elimination of cost- and time-consuming preprocessing and postprocessing steps.[5–8] In other words, the purpose of DMLS is to fabricate functional metallic parts in a single process.[9,10] Usually, liquid phase sintering (LPS) acts as a feasible bonding mechanism in direct laser sintering of metal powder.[11–15] Similar to the conventional furnace LPS, some physical aspects such as wettability, viscosity, and solidliquid ratio are significant parts in determining the final quality of sintered materials.[16,17] However, previous research efforts have demonstrated that DMLS is a complex metallurgical process exhibiting multiple modes of heat and mass transfer, and, in some instances, chemical reactions.[6,12] Meanwhile, these complex phenomena are strongly material dependent and are governed by the material’s chemical constitutions and its optical, thermal, and rheological properties.[9] Thus, a number of metal powder systems could be sintered very well using furnace LPS but could not be sintered using DMLS. Generally, the metal powder systems that have been investigated for DMLS could be classified into three categories: single-component powder, prealloyed powder, and multicomponent powder.[18,19] Early experiments on laser sintering of the single-component powder such as Ni, Cu, Pb, Sn, and Zn through the mechanism of partial melting proved to be unsuccessful because of balling.[2,20] Balling phenomena D.D. GU, Instructor, and Y.F. SHEN, Associate Professor, are with the College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People’s Republic of China. Contact e-mail: [email protected] Manuscript submitted January 4, 2006. METALLURGICAL AND MATERIALS TRANSACTIONS B
were ascribed to the high viscosity and surface tension effects occurred in the melting of the powder with a congruent melting point.[17,20,21] To alleviate balling effect and to improve sinterability, a multiphase powder approach has been designed by using a prealloyed powder system in which melting occurs over a temperature range, or a powder mixture of various components with different melting points.[2,4,18,19] So far, prealloyed powder systems that have been investigated include Ti6Al4V,[7] Ti-25V-15Cr-2Al0.2C,[22] Alloy 625,[3] bronze,[23] and steels (stainless steel,[24] high speed steel,[12–15,25] low carbon steel,[26] and tool steel[27]). Multicomponent metal powder systems such as Fe-Cu-Ni-Fe3P,[28] Fe-Cu-W,[29] iron-graphite,[6,30] Fe-CCu-Mo-Ni,[31] Fe-Ni-Cu-P,[32] Ni-bronze-CuP,[33,34] Nialloy-Cu,[19] Cu-Sn,[20] and Cu-SCuP[4,8,35] have also been studied. Most research work focused on developing feasible materials and investigating fundamentals of DMLS.
Data Loading...
