Processability of pure Zn and pure Fe by SLM for biodegradable metallic implant manufacturing

2017 ◽  
Vol 23 (3) ◽  
pp. 514-523 ◽  
Author(s):  
Marco Montani ◽  
Ali Gökhan Demir ◽  
Ehsan Mostaed ◽  
Maurizio Vedani ◽  
Barbara Previtali
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Incomplete Fusion ◽  
Second Phase ◽  
Aisi 316L ◽  
Laser Melting ◽  
Content Type ◽  
Biodegradable Metals ◽  
Degradation Rates ◽  
Superior Mechanical Properties

Purpose This paper aims to investigate the processability by selective laser melting (SLM) of materials of potential interest for innovative biodegradable implants, pure Fe and pure Zn. The processability of these materials is evaluated with a more established counterpart in permanent implants, stainless steel. In particular, the processing conditions were studied to reduce porosity due to incomplete fusion of the powder. Design/methodology/approach In the first phase of the experiments, SLM of AISI 316L was studied through design of experiments method. The study was used to identify the significant parameters in the experimental range and estimate the fluence ranges for pure Fe and pure Zn using the lumped heat capacity model. In the second phase, SLM of pure Fe and pure Zn were studied using estimated fluence ranges. In the final phase, best conditions were characterized for mechanical properties. Findings The results showed that complete melting of AISI 316L and pure Fe could be readily achieved, whereas laser melting generated a foam-like porous structure in Zn samples. The mechanical properties of laser melt implant materials were compared to as-cast and rolled counterparts. Laser melted AISI 316L showed superior mechanical performance compared to as-cast and rolled material, whereas Fe showed mechanical performance similar to rolled mild steel. Despite 12 per cent apparent porosity, laser melted Zn exhibited superior mechanical properties compared to as-cast and wrought material because of reduced grain size. Originality/value The paper provides key processing knowledge on the SLM processability of new biodegradable metals, namely, pure Fe, which has been studied sparingly, and pure Zn, on which no previous work is available. The results prefigure the production of new biodegradable metallic implants with superior mechanical properties compared to their polymeric counterparts and with improved degradation rates compared to magnesium alloys, the reference material for biodegradable metals.

scholarly journals Effect of build orientation on the surface quality, microstructure and mechanical properties of selective laser melting 316L stainless steel

2018 ◽  
Vol 24 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Hamza Hassn Alsalla ◽  
Christopher Smith ◽  
Liang Hao
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Mechanical Performance ◽  
Laser Melting ◽  
Content Type ◽  
Microstructure And Mechanical Properties ◽  
Conventional Material

Purpose The purpose of this paper is to investigate the density, surface quality, microstructure and mechanical properties of the components of the selective laser melting (SLM) parts made at different building orientations. SLM is an additive manufacturing technique for three-dimensional parts. The process parameters are known to affect the properties of the eventual part. In this study, process parameters were investigated in the building of 316L structures at a variety of building orientations and for which the fracture toughness was measured. Design/methodology/approach Hardness and tensile tests were carried out to evaluate the effect of consolidation on the mechanical performance of specimens. Optical and electron microscopy were used to characterise the microstructure of the SLM specimens and their effects on properties relating to fracture and the mechanics. It was found that the density of built samples is 96 per cent, and the hardness is similar in comparison to conventional material. Findings The highest fracture toughness value was found to be 176 MPa m^(1/2) in the oz. building direction, and the lowest value was 145 MPa m^(1/2) in the z building direction. This was due to pores and some cracks at the edge, which are slightly lower in comparison to a conventional product. The build direction does have an effect on the microstructure of parts, which subsequently has an effect upon their mechanical properties and surface quality. Dendritic grain structures were found in oz. samples due to the high temperature gradient, fast cooling rate and reduced porosity. The tensile properties of such parts were found to be better than those made from conventional material. Originality/value The relationship between the process parameters, microstructure, surface quality and toughness has not previously been reported.

scholarly journals Improving Strength and Ductility of a Mg-3.7Al-1.8Ca-0.4Mn Alloy with Refined and Dispersed Al2Ca Particles by Industrial-Scale ECAP Processing

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 767 ◽  
Author(s):  
Ce Wang ◽  
Aibin Ma ◽  
Jiapeng Sun ◽  
Xiaoru Zhuo ◽  
He Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Dominant Role ◽  
Processing Parameters ◽  
Industrial Scale ◽  
Tensile Yield Strength ◽  
Second Phase ◽  
Processing Temperature ◽  
Angular Pressing ◽  
Superior Mechanical Properties

Tailoring the morphology and distribution of the Al2Ca second phase is important for improving mechanical properties of Al2Ca-containing Mg-Al-Ca based alloys. This work employed the industrial-scale multi-pass rotary-die equal channel angular pressing (RD-ECAP) on an as-cast Mg-3.7Al-1.8Ca-0.4Mn (wt %) alloy and investigated its microstructure evolution and mechanical properties under three different processing parameters. The obtained results showed that RD-ECAP was effective for refining the microstructure and breaking the network-shaped Al2Ca phase. With the increase of the ECAP number and decrease of the processing temperature, the average sizes of Al2Ca particles decreased obviously, and the dispersion of the Al2Ca phase became more uniform. In addition, more ECAP passes and lower processing temperature resulted in finer α-Mg grains. Tensile test results indicated that the 573 K-12p alloy with the finest and most dispersed Al2Ca particles exhibited superior mechanical properties with tensile yield strength of 304 MPa, ultimate tensile strength of 354 MPa and elongation of 10.3%. The improved comprehensive mechanical performance could be attributed to refined DRX grains, nano-sized Mg17Al12 precipitates and dispersed Al2Ca particles, where the refined and dispersed Al2Ca particles played a more dominant role in strengthening the alloys.

Evaluation and prediction of material fatigue characteristics under impact loads: review and prospects

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xintian Liu ◽  
Que Wu ◽  
Shengchao Su ◽  
Yansong Wang
Keyword(s):  
Mechanical Properties ◽  
Design Methodology ◽  
Mechanical Performance ◽  
Impact Load ◽  
Impact Loads ◽  
Content Type ◽  
Material Fatigue ◽  
Mechanical Properties Of Materials ◽  
Fatigue Characteristics ◽  
Properties Of Materials

PurposeThe properties of materials under impact load are introduced in terms of metal, nonmetallic materials and composite materials. And the application of impact load research in biological fields is also mentioned. The current hot research topics and achievements in this field are summarized. In addition, some problems in theoretical modeling and testing of the mechanical properties of materials are discussed.Design/methodology/approachThe situation of materials under impact load is of great significance to show the mechanical performance. The performance of various materials under impact load is different, and there are many research methods. It is affected by some kinds of factors, such as the temperature, the gap and the speed of load.FindingsThe research on mechanical properties of materials under impact load has the characteristics as fellow. It is difficult to build the theoretical model, verify by experiment and analyze the data accumulation.Originality/valueThis review provides a reference for further study of material properties.

Selective laser melting of magnesium AZ31B alloy powder

2019 ◽  
Vol 26 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Andrzej Pawlak ◽  
Patrycja E. Szymczyk ◽  
Tomasz Kurzynowski ◽  
Edward Chlebus
Keyword(s):  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Alloy Powder ◽  
Az31 Alloy ◽  
Optimum Process ◽  
Laser Melting ◽  
Content Type ◽  
Fine Grained ◽  
Az31b Alloy ◽  
Hot Rolled

Purpose This paper aims to discuss the results of material tests conducted on specimens manufactured from AZ31 alloy powder by selective laser melting (SLM) technology. The manufactured specimens were then subjected to porosity assessment, microstructure analysis as well as to mechanical and corrosion tests. Design/methodology/approach SLM process was optimized using the design of experiments tools. Experiments aimed at selecting optimum process parameters were carried out in accordance with a five-level rotatable central composite design. Findings The porosity results showed very low values of <1 per cent, whereas mechanical properties were close to the values reported for the reference wrought AZ31 alloy in hot-rolled state. A fine-grained microstructure was observed with a large range of grain size, which enhanced the material’s mechanical properties. Corrosion characteristics of the SLM-manufactured material exceed those determined for the wrought material. Originality/value The results presented in this paper drive interest in magnesium alloys used in additive manufacturing processes. Low porosity, good mechanical properties, form of the microstructure and, most importantly, improved corrosion characteristics suggest that SLM provides great potential for the manufacture of ultralight structures, including resorbable metallic implants.

scholarly journals Alloying and Processing Effects on the Microstructure, Mechanical Properties, and Degradation Behavior of Extruded Magnesium Alloys Containing Calcium, Cerium, or Silver

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 391 ◽  
Author(s):  
Jan Bohlen ◽  
Sebastian Meyer ◽  
Björn Wiese ◽  
Bérengère J. C. Luthringer-Feyerabend ◽  
Regine Willumeit-Römer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloys ◽  
Processing Parameters ◽  
Second Phase ◽  
Degradation Behavior ◽  
Microstructure Development ◽  
Corrosion Properties ◽  
Second Phase Particles ◽  
Degradation Rates ◽  
The Relationship

Magnesium alloys attract attention as degradable implant materials due to their adjustable corrosion properties and biocompatibility. In the last few decades, especially wrought magnesium alloys with enhanced mechanical properties have been developed, with the main aim of increasing ductility and formability. Alloying and processing studies allowed demonstrating the relationship between the processing and the microstructure development for many new magnesium alloys. Based on this experience, magnesium alloy compositions need adjustment to elements improving mechanical properties while being suitable for biomaterial applications. In this work, magnesium alloys from two Mg-Zn series with Ce (ZE) or Ca (ZX) as additional elements and a series of alloys with Ag and Ca (QX) as alloying elements are suggested. The microstructure development was studied after the extrusion of round bars with varied processing parameters and was related to the mechanical properties and the degradation behavior of the alloys. Grain refinement and texture weakening mechanisms could be improved based on the alloy composition for enhancing the mechanical properties. Degradation rates largely depended on the nature of second phase particles rather than on the grain size, but remained suitable for biological applications. Furthermore, all alloy compositions exhibited promising cytocompatibility.

Effect of post-heat treatment cooling on microstructure and mechanical properties of selective laser melting manufactured austenitic 316L stainless steel

2020 ◽  
Vol 26 (10) ◽  
pp. 1739-1749
Author(s):  
Saad Waqar ◽  
Jiangwei Liu ◽  
Qidong Sun ◽  
Kai Guo ◽  
Jie Sun
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
316L Stainless Steel ◽  
Laser Melting ◽  
Content Type ◽  
Post Annealing ◽  
Cooling Conditions ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated

Purpose This paper aims to investigate the influence of different post-annealing cooling conditions, i.e. furnace cooling (heat treatment (HT) 1 – slow cooling) and air cooling (HT 2 – fast cooling), on the microstructure and mechanical properties of selective laser melting (SLM) built austenitic 316L stainless steel (SS). Design/methodology/approach Three sets of 316L SS samples were fabricated using a machine standard scanning strategy. Each set consists of three tensile samples and a cubic sample for microstructural investigations. Two sets were subsequently subjected to annealing HT with different cooling conditions, i.e. HT 1 and HT 2, whereas one set was used in the as-built (AB) condition. The standard metallographic techniques of X-ray diffraction, scanning electron microscopy and electron back-scattered diffraction were used to investigate the microstructural variations induced by different cooling conditions. The resultant changes in mechanical properties were also investigated. Findings The phase change of SLM fabricated 316L was observed to be independent of the investigated cooling conditions and all samples consist of austenite phase only. Both HT 1 and HT 2 lead to dissolved characteristic melt pools of SLM. Noticeable increase in grain size of HT 1 and HT 2 samples was also observed. Compared with AB samples, the grain size of HT 1 and HT 2 was increased by 12.5% and 50%, respectively. A decreased hardness and strength, along with an increased ductility was also observed for HT 2 samples compared with HT 1 and AB samples. Originality/value From previous studies, it has been noticed that most investigations on HT of SLM fabricated 316L were mainly focused on the HT temperature or holding time. However, the post-HT cooling rate is also an equally important factor in deciding the microstructure and mechanical properties of heat-treated components. Therefore, this paper investigates the influence of different post-annealing cooling conditions on microstructure and mechanical properties of SLM fabricated 316L components. This study provides a foundation for considering the post-HT cooling rate as an influential parameter that controls the properties of heat-treated SLM components.

Optimized cerium addition for microstructure and mechanical properties of SAC305

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Riaz Muhammad ◽  
Umair Ali
Keyword(s):  
Mechanical Properties ◽  
Solder Joint ◽  
Mechanical Performance ◽  
Tensile Specimen ◽  
Boundary Structure ◽  
Fracture Dislocation ◽  
Content Type ◽  
Microstructure And Mechanical Properties ◽  
And Performance ◽  
Tin Silver Copper

Purpose This paper aims to analyze the effect of cerium addition on the microstructure and the mechanical properties of Tin-Silver-Copper (SAC) alloy. The mechanical properties and refined microstructure of a solder joint are vital for the reliability and performance of electronics. SAC305 alloys are potential choices to use as lead-free solders because of their good properties as compared to the conventional Tin-Lead solder alloys. However, the presence of bulk intermetallic compounds (IMCs) in the microstructure of SAC305 alloys affects their overall performance. Therefore, addition of cerium restrains the growth of IMCs and refines the microstructure, hence improving the mechanical performance. Design/methodology/approach SAC305 alloy is doped with various composition of xCerium (x = 0.15, 0.35, 0.55, 0.75, 0.95) % by weight. Pure elements in powdered form were melted in the presence of argon with periodic stirring to ensure a uniform melted alloy. The molten alloy is then poured into a pre-heated die to obtain a tensile specimen. The yield strength and universal tensile strength were determined using a fixed strain rate of 10 mm per minute or 0.1667 mm s^(−1). The IMCs are identified using X-ray diffraction, whereas the elemental phase composition and microstructure evolution are, respectively, examined by using electron dispersive spectroscopy and scanning electron microscopy. Findings Improvement in the microstructure and mechanical properties is observed with 0.15% of cerium additions. The tensile test also showed that SAC305-0.15% cerium exhibits more stress-bearing capacity than other compositions. The 0.75% cerium doped alloy indicated some improvement because of a decrease in fracture dislocation regions, but microstructure refinement and the arrangement of IMCs are not those of 0.15% Ce. Different phases of Cu_6 Sn_5, Ag_3 Sn and CeSn_3 and ß-Sn are identified. Therefore, the addition of cerium in lower concentrations and presence of Ce-Sn IMCs improved the grain boundary structure and resulted refinement in the microstructure of the alloy, as well as an enhancement in the mechanical properties. Originality/value Characterization of microstructure and evaluation of mechanical properties are carried out to investigate the different composition of SAC305-xCerium alloys. Finally, an optimized cerium composition is selected for solder joint in electronics.

Structure and mechanical behavior of Big Area Additive Manufacturing (BAAM) materials

2017 ◽  
Vol 23 (1) ◽  
pp. 181-189 ◽  
Author(s):  
Chad E. Duty ◽  
Vlastimil Kunc ◽  
Brett Compton ◽  
Brian Post ◽  
Donald Erdman ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Performance ◽  
Research Effort ◽  
Small Scale ◽  
Second Phase ◽  
Initial Development ◽  
Imperfect Contact ◽  
Content Type ◽  
Oak Ridge ◽  
Printed Materials

Purpose This paper aims to investigate the deposited structure and mechanical performance of printed materials obtained during initial development of the Big Area Additive Manufacturing (BAAM) system at Oak Ridge National Laboratory. Issues unique to large-scale polymer deposition are identified and presented to reduce the learning curve for the development of similar systems. Design/methodology/approach Although the BAAM’s individual extruded bead is 10-20× larger (∼9 mm) than the typical small-scale systems, the overall characteristics of the deposited material are very similar. This study relates the structure of BAAM materials to the material composition, deposition parameters and resulting mechanical performance. Findings Materials investigated during initial trials are suitable for stiffness-limited applications. The strength of printed materials can be significantly reduced by voids and imperfect fusion between layers. Deposited material was found to have voids between adjacent beads and micro-porosity within a given bead. Failure generally occurs at interfaces between adjacent beads and successive layers, indicating imperfect contact area and polymer fusion. Practical implications The incorporation of second-phase reinforcement in printed materials can significantly improve stiffness but can result in notable anisotropy that needs to be accounted for in the design of BAAM-printed structures. Originality/value This initial evaluation of BAAM-deposited structures and mechanical performance will guide the current research effort for improving interlaminar strength and process control.

scholarly journals Enhancement of the Mechanical Performance of Stainless Steel Micro Lattice Structures Using Electroless Plated Nickel Coatings

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 494 ◽  
Author(s):  
Recep Gümrük ◽  
Altuğ UŞUN ◽  
Robert Mines
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Mechanical Performance ◽  
Cellular Materials ◽  
Coating Process ◽  
Lattice Structures ◽  
Laser Melting ◽  
Coating Technology ◽  
Specific Strength ◽  
Nickel Coatings

The use of nickel electroless plating to enhance the mechanical properties of stainless steel micro lattice structures manufactured using selective laser melting is described. A coating thickness of 17 μm is achieved, and this increases micro lattice specific stiffness by 75% and specific strength by 50%. There is scope for improving the coating process, and hence improving micro lattice mechanical performance. The methodology described here provides a new potential for optimizing micro lattice mechanical performance and can be extended to other cellular materials with different coating technology.

Microstructures and Mechanical Properties of Stainless Steel AISI 316L Processed by Selective Laser Melting

2014 ◽  
Vol 783-786 ◽  
pp. 898-903 ◽  
Author(s):  
Anne Mertens ◽  
Sylvie Reginster ◽  
Quentin Contrepois ◽  
Thierry Dormal ◽  
Olivier Lemaire ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
Uniaxial Tensile ◽  
Layer By Layer ◽  
Aisi 316L ◽  
Laser Melting ◽  
Uniaxial Tensile Testing ◽  
Steel Aisi ◽  
Stainless Steel Aisi

In this study, samples of stainless steel AISI 316L have been processed by selective laser melting, a layer-by-layer near-net-shape process allowing for an economic production of complex parts. The resulting microstructures have been characterised in details in order to reach a better understanding of the solidification and consolidation processes. The influence of the processing parameters on the mechanical properties was investigated by means of uniaxial tensile testing performed on samples produced with different main orientations with respect to the building direction. A strong anisotropy of the mechanical behaviour was thus interpreted in relation with the microstructures and the processing conditions.

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