Browsing by Author "Mousapour, Mehrdad"

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3d printing of a continuous carbon fiber reinforced bronze-matrix composite using material extrusion
(2025-01-15) Mousapour, Mehrdad; Kumar, S. Siddharth; Partanen, Jouni; Salmi, Mika
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The main objective of this study is to investigate, for the first time, the feasibility of 3d printing a continuous carbon fiber (CCF) reinforced metal matrix composite using a cost-effective material extrusion (MEX) technology. Notably, this paper presents a detailed analysis of the microstructure and mechanical and physical properties of a bronze matrix composite reinforced with CCF. The results reveal that CCF significantly impedes the expected densification levels of the composite's structure, causing extensive gaps between the bronze particles. However, despite the high porosity level, the composite's electrical conductivity remains relatively high, demonstrating the limited negative impact of the CCF material on the composite's conductivity. Moreover, mechanical evaluations were performed through 3-point bending and tensile tests, highlighting the composite material's advantages and limitations. The results show that the composite material exhibits an improved yield stress of 76 %, increased ultimate tensile strength of 20 %, and an extended fracture strain of 30 %. However, the flexural strength decreases by 23 % due to the presence of massive gaps formed by CCF.
Feasibility study of producing multi-metal parts by Fused Filament Fabrication (FFF) technique
(2021-07) Mousapour, Mehrdad; Salmi, Mika; Klemettinen, Lassi; Partanen, Jouni
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Additive manufacturing, or more commonly 3D printing, has been recently established as one of the most advanced technologies for fabricating multi-material parts. In this work, the possibility of manufacturing multi-metal parts by material extrusion process was studied for the first time. Three types of samples, named mixed, coupled and graded, resulting from deposition of two ferrous alloys: high carbon iron and stainless steel 316 L filaments, were successfully printed. After de-binding with different heating rates, they were isothermally sintered in the range of 1310−1400 °C for various holding times in argon atmosphere. Finally, some properties of the final parts, such as relative density, shrinkage, microstructural evolution, and hardness were analyzed. In conclusion, the relative density was measured up to 92 %, and the shrinkage recorded for the samples ranged between 10 % and 40 %. Based on the performed analyses, a relatively homogeneous microstructure was observed in the mixed sample, which indicates that the affordable metal extrusion technique could replace the conventional methods for metallic alloying.
Metalliosien valmistus allasvalopolymerisaatiolla
(2022-05-03) King, Daniel
Insinööritieteiden korkeakoulu | Bachelor's thesis
Multi-metal 3D printing with extrusion method
(2020-10-20) Mousapour, Mehrdad
Kemian tekniikan korkeakoulu | Master's thesis
3D printing has always been known as one of the most advanced technologies to produce various parts in a wide range of materials. Recently, fabrication of multi material parts has been considered by additive manufacturing technologies. The aim of this work is the feasibility study of manufacturing multi-metal parts by material extrusion technique, deposited from two different metal filaments within a single printing session. In this master thesis, a brief description of additive manufacturing techniques, their benefits, limitations, and applications were first presented. Then, in experimental work, three stages including printing, de-binding and sintering were studied, and the results compared. According to this, two ferrous alloy filaments i.e. stainless steel 316L and high carbon iron were chosen for printing a couple and a mixed sample. The samples, after de-binding, were isothermally sintered at different target temperatures in the range of 1310-1400 °C for 1h and 6h in argon atmosphere. The sintered samples were cooled down to ambient temperature inside the furnace with slow rate. Finally, sintered density, dimensional changes, and microstructural evolution of the final parts were also investigated. In conclusion, both couple and mixed types of multi-metal parts were successfully fabricated by fused filament fabrication. The final parts became dense up to 84% and 87% of theoretical density for couple and mixed samples, respectively. Also the amount of shrinkage was around 23% for couple sample, and 12% for mixed sample. Since the surface quality of the sintered samples were not as high as it is acceptable, a post-processing such as machining, sanding or filing is required.
NiTiCu alloy from elemental and alloyed powders using vat photopolymerization additive manufacturing
(2023-09-25) Mousapour, Mehrdad; Partanen, Jouni; Salmi, Mika
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The metal vat photopolymerization technique (MVP) has high potential for metal part production because of its high accuracy, speed, and flexibility. However, low density, poor mechanical properties, and effects of sintering parameters on the properties are some of the challenges in MVP. This paper is the first to investigate the possibility of producing a NiTiCu metal alloy using VP from Ni, Ti, and Cu elemental and mechanically alloyed powders. The effect of particle size distribution and solid content on the physical and mechanical properties is also studied and compared. The results indicate that all three elements are homogeneously distributed in the whole print without premixing the powders, which considerably reduces processing time. Finer particle size and higher solid content also improve densification degree, hardness, flexural strength, and surface quality of the final parts. The measured surface roughness (Ra) of NiTiCu was 6.42 µm and 10.31 µm for milled and elemental powders, respectively. However, the mechanical properties of NiTiCu produced by VP in this study remain insufficient and in need of further improvement.
The Oxidation of Copper in Air at Temperatures up to 100 °C
(2021-10-25) Aromaa, Jari; Kekkonen, Marko; Mousapour, Mehrdad; Jokilaakso, Ari; Lundström, Mari
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The aim of this study was to investigate the oxidation kinetics of copper at low temperatures (60 °C to 100 °C) in air by isothermal thermogravimetric analysis (TGA) and quartz crystal microbalance (QCM). The weight change in thermogravimetric tests showed periodic weight increase and decrease. In thermogravimetric tests the mass of the copper sample increased until the oxidation gradually slowed down and finally started to decrease due to cracking and spalling of the oxide formed on the surface. In QCM tests using electrodeposited copper film, the weight change was rapid at the beginning but slowed to a linear relationship after few minutes. Temperature and exposure time appeared to have a large effect on oxide film thickness and composition. With QCM, oxidation at 60–80 °C produced less than 40 nm films in 10 days. Oxidation at 90–100 °C produced 40 nm thick films in a day and over 100 nm films in a week. Although SEM-EDS analyses in TGA tests indicated that oxygen was adsorbed on the copper surface, neither XRD patterns nor Raman spectroscopy measurements showed any trace of Cu2O or CuO formation on the copper surface. Electrochemical reduction analysis of oxidized massive copper samples indicated that the oxide film is mostly Cu2O, and CuO develops only after several days at 90–100 °C.
Production, process and properties of 3d printed multi-metal parts
(2024) Mousapour, Mehrdad
School of Engineering | Doctoral dissertation (article-based)
Additive manufacturing (AM), also known as 3D printing, is an advanced technology that enables the fabrication of multi-material parts with intricate internal structures and lightweight lattice designs. Compared to conventional manufacturing methods, AM offers opportunities for engineering optimization and performance enhancements. Its material efficiency minimizes waste and usage, aligning with sustainability goals and economic considerations. Particularly, multi-metal parts additive manufacturing (MMAM) represents a transformative approach that integrates multiple metals within a single component, leading to superior material properties, structural complexity, and functional optimization. Despite its promising potential, multi-metal AM faces several limitations and challenges. Key issues include maintaining metallurgical compatibility between dissimilar metals, controlling thermal stresses and distortions during the process, achieving high-quality interfaces between different materials, and high production costs associated with some specific AM technologies. Additionally, the development of reliable process parameters, effective post-processing techniques, and robust quality control methods remains critical for the widespread adoption of multi-metal AM. Addressing these challenges is essential to unlock the full potential of multi-metal additive manufacturing and expand its applications across various industries, including aerospace, automotive, and biomedical engineering. This dissertation explores the feasibility of utilizing cost-effective additive manufacturing (AM) technologies to produce multi-metal parts. The study evaluates the properties, challenges, and limitations associated with this manufacturing approach, providing valuable insights into its potential applications and advancements in the field of multi-metal AM. Additionally, the interface between the two metals is specifically characterized in terms of their microstructural features, including porosity, intermetallic compound formation, and hardness mismatch. The dissertation employs material extrusion (MEX) and vat photopolymerization (VPP) additive manufacturing methods, known for their high availability and cost-effectiveness. These desktop printers are widely utilized in engineering, product design, dentistry, and other fields requiring high-resolution, intricate 3D printed parts. However, multi-metal parts produced using MEX and VPP technologies often exhibit poor mechanical properties inherent to sintered parts, primarily due to high levels of porosity. The de-binding process results in the formation of voids among the metal particles, making it challenging to diminish these voids during the sintering process, even with elevated temperatures and prolonged durations.