Effects of laser processing parameters on the mechanical properties, topology, and microstructure of additively manufactured porous metallic biomaterials: A vector-based approach. (15th November 2017)

• Record Type: Journal Article
• Authors: Ahmadi, S.M.; Hedayati, R.; Ashok Kumar Jain, R.K.; Li, Y.; Leeflang, S.; Zadpoor, A.A.
• Is Part Of: Materials & design. Volume 134(2017)
• Page Start: 234
• Page End: 243
• Publication Date: 2017-11-15
• Subjects: Porous biomaterials -- SLM -- Additive manufacturing -- Exposure time -- Laser power -- Mechanical properties; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2017.08.046
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Additively manufactured (AM) porous structures are a new class of biomaterials with many advantages as compared to conventionally produced biomaterials. The goal of this study was to find out how the laser processing parameters including laser power and exposure time affect the mechanical properties, topology, and microstructure of porous biomaterials AM using a novel vector-based approach. Several cylindrical porous specimens were additively manufactured using a wide range of exposure time and laser power. The effects of those parameters on the surface roughness, strut diameter, relative density, hardness, elastic modulus, yield stress, first maximum stress, and plateau stress of the porous structures were studied. The results showed that the rate of change in mechanical and topological properties with respect to exposure time was non-linear while it was linear with respect to the laser power. The results also showed that the effects of laser power and exposure time on the mechanical properties and topology of AM porous structures could be decoupled from each other, enabling derivation of predictive emperical relationships. The emperical and experimental curves showed very good agreement, which further validates the validity of the separation method used for obtaining the emperical relationships. The analytical relationships for elastic modulus and yield stress that we had obtained in a previous study could predict the elastic modulus and yield stress of the porous strucutres when the energy input was high enough (i.e. exposure times ≥ 450 μs), because the local mechanical properties of the matrix material decreased for the lower levels of energy input. The change in the mechanical properties of the bulk material due to change in laser processing parameters should thus be taken into account. Graphical abstract: Highlights: Additive manufacturing of porous materials using a vector technique is introduced. Empirical relationships are presented for prediction of topological/mechanical properties. Mechanical properties increase with increasing either laser power or scanning time. The effects of laser power and exposure time could be decoupled.