Densification of alumina components via indirect selective laser sintering combined with isostatic pressing

Wei

Int J Adv Manuf Technol

et al. 2015

This study investigated the selective laser sintering (SLS) of aliphatic-polycarbonate/hydroxyapatite (a-PC/HA) composite scaffolds for medical applications. The effects of material ratios and SLS processing parameters on the porosity, microstructures and mechanical properties of the samples were observed. The optimized proportion in the a-PC/HA composite was found to be 10 wt% HA. The processing parameters were optimized as: 10 W of laser power, 2000 mm/s of scan speed, 0.15 mm of scan spacing, and 0.17 mm of layer thickness. With the optimized process, the scaffold porosity and compressive module were increased to 77.36 % and 26 MPa, respectively. The pores were interconnected, indicating the existence of more space for cell ingrowth and the improvement in the load capability of bone scaffold. The nanoscale HA particles were fully or partially embedded in a-PC matrix and did not decompose during the SLS processing. Crystalline behavior, bioactive activity, and osteoconduction, beneficial for bone ingrowth, scarcely changed before and after sintering. The successful manufacturing of complex scaffold with smooth surface demonstrated that surface roughness could be controlled by optimizing HA content and adjusting the processing parameters. The a-PC/HA composite powder could be used to manufacture complex porous parts by using the SLS process for medical applications.

Section: Materials Characterizationmentioning

confidence: 99%

Selective laser sintering of aliphatic-polycarbonate/hydroxyapatite composite scaffolds for medical applications

Wei

Int J Adv Manuf Technol

et al. 2015

“…Hot isostatic pressing (HIP) as one of material processing approaches has been wildly used to fabricate near-net shape parts with near full density and high properties, which involves a process of high temperature and pressure with gas. This method can produce the hardcutting and precious metal and ceramic components directly from powders [3,4]. During HIP process, the porosity can be completely eliminated through the powder grain-coupled deformation mechanism [5]; however, the high pressure generally leads to severe deformation of the capsule.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation and experimental investigation on densification, shape deformation, and stress distribution of Ti6Al4V compacts during hot isostatic pressing

Zhou

Int J Adv Manuf Technol

Xue

et al. 2016

Self Cite

Hot isostatic pressing of metal powders involves a complex thermal and mechanical coupling process. A constitutive model based on Perzyna's elastic-viscoplasticity equation was proposed, and a Lagrangian finite element method was applied to analyze the large deformation, nonlinear friction, powder flow, and densification behavior during hot isostatic pressing. The mechanical behavior of the powders was analyzed in terms of stress distribution. For comparison to the simulation results, the density, shape deformation, and residual stress of the specimens were evaluated using Archimedes' principle, 3D measuring technology, and Empyrean X-ray diffractometer.

“…Infiltration is generally divided into natural infiltration, vacuum infiltration and pressure infiltration, commonly used infiltration of silica sol, alumina sol, what Isostatic pressing technology is to place the product in a closed container, through the pressure medium, apply uniform pressure to the product to improve product density [79]. According to the different temperature during the pressure process, the isostatic pressing is divided into cold isostatic pressing and hot isostatic pressing.…”

Section: Post-processing Processmentioning

confidence: 99%

Study and Application Status of Additive Manufacturing of Typical Inorganic Non-metallic Materials

Yun¹,

Shi²,

Ma³

et al. 2019

Additive manufacturing is a rapid manufacturing based on discrete accumulation to achieve prototypes or parts of products. Inorganic non-metallic materials, as one of the three major materials, have incomparable application prospect in medical, aerospace, automotive, construction, arts and crafts, as well as many other fields. In order to rapidly create devices with arbitrarily complex shapes, additive manufacturing of inorganic non-metallic materials is becoming a hot spot of current research. In view of the technical types, materials and other aspects, this article introduced research status and development of additive manufacturing in inorganic non-metallic materials at home and abroad. Several common inorganic non-metallic materials are compared and analyzed, such as Al2O3, Si3N4 SiO2, ZrO2, etc. The forming characteristics and the problems of several popular ceramic materials and sand–casting materials are illustrated with emphases. The key problems existed in additive manufacturing forming process of inorganic non-metallic material are pointed out and urgent to be solved at present. Furthermore, the impacts of the material handling process, three dimensional printing (3DP), Selective Laser Sintering(SLS), Selective Laser Melting (SLM) three-dimensional forming processes and post treatment process on the quality and performance of the forming parts are analyzed. Finally, the prospects in SLS of the gem material are put forward.