Jacopo Fiocchi

• Doctor of Philosophy
• Researcher at Institute of Condensed Matter Chemistry and Technologies for Energy, Italian National Research Council

Biodegradable alloys are promising biomaterials for realizing temporary implantable devices. Surface properties have a significant impact on the degradability of such materials; therefore, their modification can open interesting opportunities for controlling the dissolution in biological environment. At an industrial level, ultra-short pulse laser...

The interest in the joining of Cu and Al alloys for some industrial sectors, such as the electrical mobility one, has been growing in recent years, despite their difficulties in laser based processing. Welding by means of lasers operating in the near-infrared (n-IR) field (typically 1060 nm) suffers from the low absorption coefficient of highly ref...

Fe-Mn based alloys are particular promising for the development of temporary bioabsorbable implants. They exhibit good performance in biological tests, improved mechanical properties and more adequate degradation rates than pure iron for the targeted application. In addition, this system possesses an excellent processability, making it particular s...

Tailoring microstructure by processing and heat treatments to optimize: B2 Cu-particle distribution, mechanical properties and degradation. In vitro assessment of cytocompatibility, hemocompatibility, antibacterial effect.

Among Additive Manufacturing (AM) technologies, Laser Powder Bed Fusion (LPBF) has made a great contribution to optimizing the production of customized implant materials. However, the design of the ideal surface topography, capable of exerting the best biological effect without drawbacks, is still a subject of study. The aim of the present study is...

Additive manufacturing of architected materials, particularly lattice or porous structures, has garnered significant interest in recent years due to its ability to enhance weight-to-strength performance, load-bearing capabilities, and superior energy absorption. Integrating these structures with shape memory alloys (SMAs) introduces unique function...

Additively manufactured medical devices require proper surface finishing before their use to remove partially adhered particles and provide adequate surface roughness. The literature widely investigates regular lattice structures—mainly scaffolds with small pores to enhance osseointegration; however, only a few studies have addressed the impact of...

An equiatomic CoCuFeMnNi high entropy alloy was subjected to laser beam welding and the effect of two post-weld thermal treatments (i.e. solution treatment and direct ageing) was studied. Multiple characterisation techniques were implemented to correlate the local mechanical behaviour (evaluated by direct image correlation) to the microstructural e...

Biodegradable metals represent a valuable solution for the development of temporary vascular implants. These are expected to dissolve in the body over time, avoiding side effects typical of permanent implants, such as thrombosis, in-stent restenosis and chronic inflammation. Iron (Fe)-based alloys, such as iron–manganese (Mn) alloys, are of particu...

The equiatomic MoNbTaTiZr biocompatible and refractory high-entropy alloy (RHEA) was additively manufactured by laser powder bed fusion (LPBF). The possibility to reduce the cracking susceptibility of the RHEA during LPBF was investigated. By the addition of pure B to the RHEA powder feedstock, the in-situ precipitation of boride particles was prom...

Superelastic NiTi (Nitinol) alloy is a smart material applied in the biomedical sector for devices, such as stents, implants and orthodontic wires. Nevertheless, after surgery, one of the major causes of failure, which requires the explantation of the device, is linked to bacterial infections. Therefore, development of antibacterial materials becom...

In recent years, the interest in shape memory alloys with high transformation temperatures (HTSMA) has significantly increased not only in the academic sphere, but also due to a market-push, especially from aerospace, automotive, and robotics. However, a real break-through has not been achieved yet because of several problems: Lower chemistry contr...

Despite the evident existence of market demand and great efforts in alloy development and processing, non-binary NiTi alloys struggle to exploit their full potential and to satisfy the high expectations from industry. Two exemplary fields of research are low-hysteresis (LH-SMA) and high temperature shape memory alloys (HT-SMA), in which many alloy...

Background and Objectives: Spring-assisted surgery is a popular option for the treatment of non-syndromic craniosynostosis. The main drawback of this procedure is the need for a second surgery for spring removal, which could be avoided if a distractor material could be metabolised over time. Iron–Manganese alloys (FeMn) have a good trade-off betwee...

Copper based alloys are promising materials for electrical and thermal devices. In this respect, the use of laser powder bed fusion (LPBF) allows the realization of 3D complex structures, possibly enhancing the functional performances of such devices. LPBF also induces refined microstructures and build-up of residual stresses, due to the rapid soli...

Prosthetic reconstruction can serve as a feasible alternative, delivering both functional and aesthetic benefits to individuals with hand and finger injuries, frequent causes of emergency room visits. Implant-related infections pose significant challenges in arthroplasty and osteosynthesis procedures, contributing to surgical failures. As a potenti...

Purpose The present study investigates the mechanical properties of three types of Ti6Al4V ELI bone screws realized using the laser powder bed fusion (LPBF) process: a fully threaded screw and two groups containing differently arranged sectors made of lattice-based Voronoi (LBV) structure in a longitudinal and transversal position, respectively. Th...

The present work explores the possibility of processing a CoCuFeMnNiTi0.13 high-entropy alloy by laser powder bed fusion (LPBF). The alloy, produced under optimised processing conditions, presents good densification but also hot cracks, caused by the liquation of an inter-dendritic Cu-rich phase. Microstructure of the as-built alloy is characterise...

Copper based alloys are promising materials for electrical and thermal devices. In this respect, the use of laser powder bed fusion (LPBF) allows the realization of 3D complex structures, possibly enhancing the functional performances of such devices. LPBF also induces refined microstructures and build-up of residual stresses, due to the rapid soli...

Thumb amputations leads to 50 % loss in hand functionality. To date, silicone vacuum prosthesis and autologous transplantation are the most adopted treatment solutions: nevertheless, vacuum prostheses lack in stability and cause skin issue and surgical treatment is not always accepted by patients. Osseointegrated implants were demonstrated to enhan...

Strengthening mechanisms, which are commonly exploited by conventional alloys, can be effectively incorporated in high entropy alloys (HEAs) to improve their mechanical behaviour. In this light, compositional modification of equiatomic HEAs can be pursued in order to obtain specific microstructural features. Herein, a face centred cubic CoCuFeMnNi...

Among metallic biomaterials, near-equiatomic NiTi is one of the most promising intermetallic system applicable for biomedical applications, thanks to its high biocompatibility and unique superelasticity (or pseudoelasticity), offering a complete recoverable strain up to 8%. In the prospective uses for bio-devices, the surface processing of NiTi med...

Nowadays, additive manufacturing (AM) of NiTi shape memory alloy is a challenging topic for the realization of 3D functional parts. Particularly, Laser Powder Bed Fusion (LPBF) of NiTi powder is one of the most challenging processes belonging to AM, thanks to its best performances in terms of productivity and precision of geometrical complexity. Th...

Three techniques for the assessment of the fatigue response of AMed parts are compared: defect analysis and subsequent theoretical estimation of the fatigue strength with micro-CT, infrared thermography and ultrasonic fatigue testing. Experimental tests on AlSi10Mg specimens are carried out and proved that each investigated technique can be used fo...

In the present work the possibility of processing a CoCuFeMnNiTi high entropy alloy by laser powder bed fusion (LPBF) is explored. Such composition was specifically tailored with the aim of allowing the precipitation of strengthening second phases during post-processing ageing treatment. A suitable processing window was found by varying processing...

The present work explores the feasibility of joining the CoCuFeMnNi high entropy alloy by laser beam welding. An appropriate feasibility window is identified, and the optimal process parameters (300 W power, scanning speed 20 mm s⁻¹, spot size 0.45 mm) are related to the properties of the studied material. Cu's tendency to segregate from other allo...

Since several years the need for realizing small and smart devices composed of functional materials is constantly increasing. Among this advanced materials, shape memory alloys (SMAs) are some of the most important functional materials in several applications, including in the biomedical and aerospace fields. Nowadays, laser cutting is probably the...

Biodegradable metallic alloys are promising materials for the development of temporary medical implants, including cardiovascular and orthopedic devices. The present work explores the surface modification of a biodegradable Fe–20Mn alloy by means of ultrashort laser texturing and the correlation between the laser‐induced surface morphology and the...

Dedicated thermal treatments can improve the mechanical behaviour of high entropy alloys (HEAs) by producing nanostructured microstructures with improved characteristics. Herein, the inherent metastability of an equiatomic CoCuFeMnNi alloy was exploited to induce the formation of secondary phases upon ageing treatment. Advanced characterization tec...

This paper experimentally investigates the effect of the specimen volume (size-effect) on the Very-High-Cycle-Fatigue (VHCF) response of SLM AlSi10Mg specimens. Tension-compression tests are carried out on hourglass and Gaussian specimens with different risk-volumes produced in horizontal and vertical direction. Experimental results show that size-...

The present invention relates to bioresorbable Fe-Mn-Si-X metal alloys compositions, with controllable biodegradation rates and excellent mechanical properties, having the following composition in weight percent: iron from 65 wt% to 75wt%, manganese from 25 wt% to 35 wt% and silicon from 0.5 wt% to 6 wt%, the additional compositional element X cons...

Automatic design of mechanical metamaterials is key to achieving efficiencies in terms of a desired functionality that can far exceed the rationally designed man-made solutions. Here, we introduce a discrete element model capable of describing the mechanical response of three-dimensional trussed structures under a predetermined external perturbatio...

The present invention relates to bioresorbable Fe-Mn-based alloys with pseudoelastic properties, with controllable and relevant biodegradation rates, excellent mechanical properties and their use for medical implants, in particular vascular implants and thin-walled implants.

The use of additive manufacturing allows the production of complex designs, including metallic lattice structures, which combine lightness and good mechanical properties. Herein, the production of AlSi10Mg lattice structures by laser powder bed fusion is explored and consistent processing parameters are selected. Thereafter, it is demonstrated that...

In the present work, surface engineering of Ti6Al4V, produced via selective laser melting parts, was carried out with the aim of investigating how surface features of substrate may improve the coupling with AlTiN coatings deposited by physical vapor deposition reactive high-power impulse magnetron sputtering. In particular, the work highlighted how...

The present work explores the effect of a stress relieving heat treatment on the microstructure, tensile properties and residual stresses of the laser powder bed fused AlSi9Cu3 alloy. In fact, the rapid cooling rates together with subsequent heating/cooling cycles occurred during layer by layer additive manufacturing production make low temperature...

In this work, the effect of the Al content (x = 5, 10, and 15 at. %) on the martensitic transformation (MT) and microstructure and mechanical properties of Cu(50−x)Zr50Alx alloys was studied. The microstructure of the alloys was characterized at room temperature by means of scanning electron microscopy and X-ray diffraction. An increase in Al conte...

The multiaxial fatigue behavior of Ti6Al4V samples, made by selective laser melting (SLM) process, was investigated in this work. Fatigue tests were carried out under three different loading conditions: (i) tensile, (ii) torsion, and (iii) in‐phase axial–torsional. A modified damage model, based on the Sines criterion, is proposed and used to analy...

Among iron-based materials, the Fe-Mn system appears to be highly suitable for the development of biodegradable metals for orthopaedic and vascular applications. The versatility of tailoring such steels by alloying provides many opportunities to customise biodegradable devices. In the field of applications where a high load-bearing capacity is requ...

Space is one of the most avant-garde sectors for additive manufacturing as the inherent characteristics of this technology allow the creation of complex and lightweight 3D structures. Using this brand-new design tool, it was possible to design the pumping system holder of the MicroMED instrument, a particle analyser developed for ExoMars 2022 missi...

The present work explores the processability of an advanced aluminum alloy, namely AlCu-TiB2, by selective laser melting (SLM), and the correlation between microstructure and mechanical properties of as built specimens. The principal process parameters of the laser emission in pulsed wave (PW) mode, namely laser power and exposure time, were varied...

Laser powder bed fusion (LPBF) is the most widely used additive manufacturing technique and has received increasing attention owing to the high design freedom it offers. The production of aluminium alloys by LPBF has attracted considerable interest in several fields due to the low density of the produced alloys. The peculiar solidification conditio...

Three new Fe-Mn-C alloys were cast, hot rolled and characterized as candidate materials for the fabrication of bioresorbable implants. In particular, the effect of different Mn and C contents on phases formation, mechanical properties as well as corrosion rate and degradation pattern in modified Hanks’ solution were investigated. A combination of c...

The interest in manufacturing complex devices with integrated extra-functional properties is steadily growing for high technological application fields, such as the aerospace and biomedical ones. Among advanced methods of manufacturing, additive manufacturing allows to produce complex three-dimensional geometries, like lattice structures, which pos...

Among additive manufacturing (AM) processes, Selective Laser Melting (SLM) is the most diffused layer by layer method for manufacturing 3D components. It is based on local melting, induced by a laser scanning, on a powder bed; the limited dimensions of the liquid pool provoke rapid cooling rates which can be associated to significantly finer micros...

The present work aims at exploring the influence of laser welding on the functional behaviour of a Fe-20Mn-0.6C (wt.%) bioabsorbable alloy. At first, the selection of the most suitable process speed (40 mm/s) was done in order to obtain a full penetration joint with limited taper. Then, microstructural and mechanical analyses of welded sheets confi...

Micro-and nanostructure investigations of AlSi10Mg alloy powders and additive manufactured samples were performed to highlight common effects related to very fast local cooling rates during production. We refer to the homogenously dispersed Si(Mg) nanoparticles and the presence of interconnected amorphous phases in the coral-like eutectic Si networ...

Nowadays, thanks to the growing interest regarding the manufacturing of 3D complex parts with integrated functionalities, the additive manufacturing of NiTi shape memory alloy is a challenging technological issue. Particularly, 3D printing of NiTi components requires a strong interaction between technological and metallurgical approaches, due to th...

Nowadays, additive manufacturing (AM) permits to realize complex metallic structural parts, and the use of NiTi alloy, known as Nitinol, allows the integration of specific functions to the AM products. One of the most promising designs for AM is concerning the use of lattice structures that show lightweight, higher than bulk material deformability,...

Additive Manufacturing (AM) techniques are under constant development and Selective Laser Melting (SLM) is among the most promising ones. However, widespread use of AM techniques in many industries is limited by the different/unusual mechanical properties of AM metallic parts, with respect to traditionally processed ones, especially when dealing wi...

It is well-known in the literature that the fatigue response of specimens produced through Additive Manufacturing (AM) processes is mainly controlled by the defect population. Nevertheless, microstructure, residual stresses and building orientation must be considered as they may also play a significant role. In the present paper, the influence of m...

Ti6Al4V specimens were produced using electron beam melting (EBM) with the goal of studying the effects of the scanning strategies on the surface morphology, microstructure, and mechanical properties. As the factory condition consists in the use of different parameters for scanning the hatch and the contour, additional processing conditions were in...

In the Additive Manufacturing (AM) field, Selective Laser Melting (SLM) process is one of the most promising manufacturing technologies for the production of 3D complex parts. High-tech sectors, like aerospace, show growing interest for the use of AM, because it can offer unique opportunities in terms of freedom in the design and integration of som...

The present work explores the possibility of employing the selective laser melting technique to produce parts in AlSi9Cu3 alloy. This alloy, currently prepared by high-pressure dye casting and intended for automotive application, may benefit from the refined microstructure commonly induced by additive manufacturing techniques. The process parameter...

The response of an AlSi10Mg alloy produced by selective laser melting (SLM) to specifically designed heat treatments is explored. Thermal phenomena of the rapidly solidified material were studied by differential scanning calorimetry (DSC), and the results have been used to define specific post-processing thermal treatment temperatures. In detail, t...

Selective laser melting (SLM) allows 3D complex parts to be produced with integrated functionalities but does not permit to realize large dimension parts, as the building chamber volume of commercial SLM systems is limited. Therefore, the possibility of joining SLM-built parts by welding appears as extremely valuable. In this work, laser weldabilit...

The interest of manufacturing complex devices is steadily growing for high technological application fields, such as the aerospace and biomedical ones, due to the possibility of coupling structural and functional properties. Additive manufacturing (AM) allows to produce 3D complex geometries such as lattice structures, offering lightness together w...

Additive Manufacturing allows to design and realize 3D parts, integrating additional functionalities offered by the interaction between complex shapes and the material properties. Results can be even more appealing when functional materials, like Shape Memory Alloys, are printed: new opportunities for smart devices can be opened. In the present bul...

In the paper, the influence of the annealing temperature on the Very High Cycle Fatigue (VHCF) of AlSi10Mg specimens produced through selective laser melting (SLM) is experimentally assessed. VHCF tests at 20 kHz are carried out on Gaussian specimens subjected to a heat treatment suggested by the system supplier (heating for 2 hours to 320°C and ai...

It is well-known that many manufacturing parameters affect the quasi-static and the fatigue response of additive manufacturing (AM) parts. In particular, due to the layer-by-layer production, the load orientation, with respect to the building direction, plays a fundamental role for the fatigue response. This paper investigates the fatigue response...

The use of additive manufacturing (AM) technique is recently increased due to its ability in producing complex-shaped components. AlSi10Mg alloy is largely employed for AM and, in particular, for selective laser melting (SLM). Hence, the interest on this alloy is growing, together with the studies to control its mechanical performances, which can b...

The present paper investigates the effect of a stress relief heat treatment (two hours at 320 °C and air cooling down) on the VHCF response of an AlSi10Mg alloy produced through SLM. Ultrasonic tension-compression tests up to 10 ⁹ cycles were carried out on as-built and heat treated Gaussian specimens with a large loaded volume. Experimental result...

Among the materials used for the production of components through Additive Manufacturing (AM) processes, the Selective-Laser-Melting (SLM) Ti6Al4V alloy is widely employed in aerospace applications for its high specific strength and in biomedical applications for its good biocompatibility. Actual structural applications are generally limited to sta...

The development and application of additive manufacturing (AM) technologies is constantly increasing. However, in many applications, AM parts are subjected to multiaxial loads, arising from operating conditions and/or complex geometries. These make AM components serious candidates for crack initiation and propagation mechanisms. Therefore, a deep u...

Currently, selective laser melting (SLM) is among the most widespread of the additive manufacturing (AM) technologies. Commercially available SLM systems can offer both continuous wave (CW) and pulsed wave (PW) emissions of the laser power. It has been demonstrated that relative density and geometric features can be affected by the laser emission p...

It is well known in the literature that fatigue is particularly critical for Additive Manufacturing (AM) parts, because internal defects originating during the AM process represent a critical site for crack initiation. In the literature, the High‐Cycle‐Fatigue (HCF) response of AM parts has been extensively investigated; however, there are few resu...

In Selective Laser Melting (SLM) both structural and functional properties of built parts are drastically affected by the process parameters, such as laser beam power, exposure time and building platform temperature. The effect of the mentioned parameters on the microstructure evolution and mechanical properties of AlSi10 Mg SLM builts were investi...

In this work a new heat treatment specific for selective laser melted (SLM) AlSi10Mg products is studied. Samples were analyzed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM); two exothermic phenomena were recognized, kinetically analyzed and associated to the precipitation of Mg2Si and to the rupture and spheroid...

Nowadays, selective laser melting (SLM) is considered as the most challenging technology for manufacturing complex components in different industrial fields, such as biomedical, aerospace and racing. It is well-known that SLM may yield to microstructures significantly different from those obtained by conventional casting, thus affecting the mechani...

High-energy ball milling was carried out to disperse SiC nanoparticles (ex-situ reinforcement) and fragments of oxide (in-situ reinforcement) in an Al2618 alloy matrix. Nanocomposite powders were consolidated by hot rolling at 600 °C. Samples produced using ball milled powder showed a weak response to ageing treatment as demonstrated by thermal and...