Main Defects Observed in Titanium GRADE II and 316L Stainless Steel Elements Obtained by Selective Laser Melting

2020 ◽  
Vol 308 ◽  
pp. 33-50
Author(s):  
Anna Woźniak ◽  
Marcin Adamiak
Keyword(s):  
Stainless Steel ◽  
Energy Density ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Defect Formation ◽  
Pure Titanium ◽  
Parameters Optimization ◽  
Laser Melting ◽  
Grade Ii ◽  
Titanium Grade

Selective Laser Melting SLM is one of the most popular three dimensional printing methods, which can be used for manufactured real elements (with high geometrical complexity) in many application, such as medicine, automotive or aerospace industries. The SLM final parts are characterized by high mechanical properties and satisfactory physicochemical properties. However, the properties of parts depend of process parameters optimization. In this paper, effects of processing parameters, such as laser power P, scanning speed SP, layer thickness t or point distance PD on defect formation and relative densities of manufactured elements are explored. For the purpose the stainless steel 316L and pure titanium Grade II are used. The process optimization were carried out according to the formula of energy density, which is delivered to the powder material. The stainless steel samples were divided into 12 groups, depends of the energy density. The titanium parts were printed at the same value of energy, and the process parameters are changed. The microscope observation and relative density measurements were carried out. Based on the obtained results, it can be confuted that the SLM parameters have a significant effect on the samples properties and the mechanism formed defect in both material are similar.

scholarly journals The Influence of Hybrid Surface Modification on the Selected Properties of CP Titanium Grade II Manufactured by Selective Laser Melting

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2829
Author(s):  
Anna Woźniak ◽  
Marcin Adamiak ◽  
Grzegorz Chladek ◽  
Mirosław Bonek ◽  
Witold Walke ◽  
...  
Keyword(s):  
Surface Modification ◽  
Selective Laser Melting ◽  
Pure Titanium ◽  
Microscopic Investigation ◽  
The Body ◽  
Laser Melting ◽  
Initial State ◽  
Tin Coatings ◽  
Grade Ii ◽  
Titanium Grade

The human body is an extremely aggressive environment in terms of corrosion. Titanium and its alloys are one of the most popular biomaterials used for implant applications due to biocompatibility. However, every element introduced into the body is treated as a foreign body. The human body’s immune response may, therefore, lead to implant rejection and the need for reoperation. For this purpose, it seems important to carry out surface modifications by applying coatings and inter alia by texturing to implants. The objective of this paper is to investigate the effect of surface treatment on the chosen properties of the pure titanium (Grade II) samples obtained by selective laser melting (SLM) processing. The samples were divided into five groups: Initial state (after polishing), after surface modification by the physical vapour deposition (PVD) method—CrN and TiN coatings were deposited on the surface of the tested material, and after laser texturing. The paper presents the results of the microscopic investigation, chemical and phase compositions, and physicochemical and electrochemical properties of the tested samples. Based on the results obtained it can be concluded that the hybrid surface modification shows significant effects on the properties of the pure titanium. The samples with the textured PVD-deposited TiN coatings were characterized by favorable physicochemical properties and were the highest performing in terms of pitting corrosion resistance.

scholarly journals Influence of the Energy Density for Selective Laser Melting on the Microstructure and Mechanical Properties of Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 919 ◽  
Author(s):  
Črtomir Donik ◽  
Jakob Kraner ◽  
Irena Paulin ◽  
Matjaž Godec
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Energy Density ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Material Properties ◽  
Beam Diameter ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
The Impact

We have investigated the impact of the process parameters for the selective laser melting (SLM) of the stainless steel AISI 316L on its microstructure and mechanical properties. Properly selected SLM process parameters produce tailored material properties, by varying the laser’s power, scanning speed and beam diameter. We produced and systematically studied a matrix of samples with different porosities, microstructures, textures and mechanical properties. We identified a combination of process parameters that resulted in materials with tensile strengths up to 711 MPa, yield strengths up to 604 MPa and an elongation up to 31%, while the highest achieved hardness was 227 HV10. The correlation between the average single-cell diameter in the hierarchical structure and the laser’s input energy is systematically studied, discussed and explained. The same energy density with different SLM process parameters result in different material properties. The higher energy density of the SLM produces larger cellular structures and crystal grains. A different energy density produces different textures with only one predominant texture component, which was revealed by electron-backscatter diffraction. Furthermore, three possible explanations for the origin of the dislocations are proposed.

Influence of Selective Laser Melting Process Parameters on Densification Behavior, Surface Quality and Hardness of 18Ni300 Steel

2020 ◽  
Vol 861 ◽  
pp. 77-82
Author(s):  
Gan Li ◽  
Cheng Guo ◽  
Wen Feng Guo ◽  
Hong Xing Lu ◽  
Lin Ju Wen ◽  
...  
Keyword(s):  
Energy Density ◽  
Relative Density ◽  
Maraging Steel ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Laser Power ◽  
Densification Behavior ◽  
Laser Melting ◽  
Scan Speed

This study investigated the effect of laser power (P), scan speed (v) and hatch space (h) on densification behavior, surface quality and hardness of 18Ni300 maraging steel fabricated by selective laser melting (SLM). The results indicated that the relative density of the SLMed samples has a shape increase from 73% to 97% with the laser energy density increasing from 0.5 to 2.2 J/mm2. The relative density ≥ 99% was achieved at the energy density in the range of 2.2~5.9 J/mm2. The optimum process parameters were found to be laser power of 150~200 W, scan speed of 600mm/s and hatch space of 0.105mm. In addition, it was found that the hardness increased initially with the increasing relative density up to relative density of 90% and then little relationship, but finally increase again significantly. This work provides reference for determining process parameters for SLMed maraging steel and the development of 3D printing of die steels.

Effects of Process Parameters on the Surface Roughness of Stainless Steel 316L Parts Produced by Selective Laser Melting

2018 ◽  
Vol 46 (4) ◽  
pp. 20170140 ◽  
Author(s):  
Derahman Nur Aqilah ◽  
Ab Karim Mohd Sayuti ◽  
Yusof Farazila ◽  
Dambatta Yusuf Suleiman ◽  
Mohd Amran Nor Amirah ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Stainless Steel 316L ◽  
Laser Melting

scholarly journals Acoustic Properties of 316L Stainless Steel Lattice Structures Fabricated via Selective Laser Melting

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 111 ◽  
Author(s):  
Xiaojing Sun ◽  
Fengchun Jiang ◽  
Jiandong Wang
Keyword(s):  
Stainless Steel ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Sound Absorption ◽  
316L Stainless Steel ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Frequency Range ◽  
Laser Melting ◽  
The Difference

A bulk specimen and two different lattice sandwich structures composed of 316L stainless steel were fabricated via selective laser melting. This study analysed the acoustic properties, including sound insulation and sound absorption, of the three kinds of structures, which were produced via selective laser melting under the same process parameters. The results showed that the difference in the unit structures, rather than microstructural difference, was the main reason for the difference in acoustic properties between the samples. Under the same process parameters, the microstructure of the different structures had the same cell structure. However, the sound absorption properties of the lattice sandwich structures were better than those of the bulk sample in the measured frequency range of 1–6.3 kHz. The lattice sandwich structure with 2.5 × 2.5 × 2.5 mm3 unit structures exhibited excellent sound insulation properties in the frequency range of 1–5 kHz.

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