Effect of preliminary laser surface treatment on mechanical properties of diffusion welded joints of Fe-Ni alloy

2020 ◽  
pp. 40-47
Author(s):  
V.N. Yolkin ◽  
◽  
T.V. Malinsky ◽  
Yu.V. Khomich ◽  
V.A. Yamshchikov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Density ◽  
Surface Treatment ◽  
Laser Treatment ◽  
Ultimate Strength ◽  
Weld Joint ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Weld Joints ◽  
Ni Alloy

The experimental studies of the effect of preliminary laser pulsed surface treatment on mechanical properties of the diffusion welding joints of Fe-Ni alloy were carried out. The alloy surfaces was treated in inert gas (Ar) environment by scanning beam of nanosecond laser pulses with a wavelength 355 nm, repetition rate 100 Hz and scanning speed 1 mm/s. Laser spot was 220 µm, the energy density 2 and 3 J/cm2. Treated samples as well as the control untreated ones were placed at the same container and were diffusion bonded by hot isostatic pressing (HIP) at the temperatures of 1000 and 1160°С. Ultimate strength and elongation of weld joint materials were determined by tensile testing. It is shown that laser pulse treatment leads to improvement both the ultimate strength and relative elongation of the weld joints. Mechanical properties of the weld joints depends on the laser energy density. Weld joint properties can be increased by optimization of the laser treatment parameters. The best results were achieved at laser energy density 2 J/cm2. Ultimate strength was increased by 12% and 29% for HIP temperatures 1160 and 1000°С respectively. The elongation values also increased from 42% for non-treated samples up to 51% for samples treated at 2 J/cm2 energy density. Preliminary laser treatment of welded surfaces permits to reduce the HIP temperature by 160°С and thereby reduce power consumption during HIP process.

scholarly journals Manufacturing of Porous Polycaprolactone Prepared with Different Particle Sizes and Infrared Laser Sintering Conditions: Microstructure and Mechanical Properties

2014 ◽  
Vol 6 ◽  
pp. 640496 ◽  
Author(s):  
G. V. Salmoria ◽  
D. Hotza ◽  
P. Klauss ◽  
L. A. Kanis ◽  
C. R. M. Roesler
Keyword(s):  
Mechanical Properties ◽  
Energy Density ◽  
Laser Energy ◽  
Flexural Modulus ◽  
Selective Laser Sintering ◽  
Polymeric Materials ◽  
Laser Sintering ◽  
Laser Energy Density ◽  
Particle Sizes ◽  
Mechanical Devices

The techniques of Rapid Prototyping, also known as Additive Manufacturing, have prompted research into methods of manufacturing polymeric materials with controlled porosity. This paper presents the characterization of the structure and mechanical properties of porous polycaprolactone (PCL) fabricated by Selective Laser Sintering (SLS) using two different particle sizes and laser processing conditions. The results of this study indicated that it is possible to control the microstructure, that is, pore size and degree of porosity, of the polycaprolactone matrix using the SLS technique, by varying the particle size and laser energy density, obtaining materials suitable for different applications, scaffolds and drug delivery and fluid mechanical devices. The specimens manufactured with smaller particles and higher laser energy density showed a higher degree of sintering, flexural modulus, and fatigue resistance when compared with the other specimens.

Selective Laser Melting Additive Manufacturing of Novel Aluminum Based Composites With Multiple Reinforcing Phases

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Dongdong Gu ◽  
Fei Chang ◽  
Donghua Dai
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Energy Density ◽  
Selective Laser Melting ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Wear Property ◽  
Laser Melting ◽  
Sic Particles

The selective laser melting (SLM), due to its unique additive manufacturing (AM) processing manner and laser-induced nonequilibrium rapid melting/solidification mechanism, has a promising potential in developing new metallic materials with tailored performance. In this work, SLM of the SiC/AlSi10Mg composites was performed to prepare the Al-based composites with the multiple reinforcing phases. The influence of the SLM processing parameters on the constitutional phases, microstructural features, and mechanical performance (e.g., densification, microhardness, and wear property) of the SLM-processed Al-based composites was studied. The reinforcing phases in the SLM-processed Al-based composites included the unmelted micron-sized SiC particles, the in situ formed micron-sized Al4SiC4 strips, and the in situ produced submicron Al4SiC4 particles. As the input laser energy density increased, the extent of the in situ reaction between the SiC particles and the Al matrix increased, resulting in the larger degree of the formation of Al4SiC4 reinforcement. The densification rate of the SLM-processed Al-based composite parts increased as the applied laser energy density increased. The sufficiently high density (∼96% theoretical density (TD)) was achieved for the laser linear energy density larger than 1000 J/m. Due to the generation of the multiple reinforcing phases, the elevated mechanical properties were obtained for the SLM-processed Al-based composites, showing a high microhardness of 214 HV0.1, a considerably low coefficient of friction (COF) of 0.39, and a reduced wear rate of 1.56 × 10−5 mm3 N−1 m−1. At an excessive laser energy input, the grain size of the in situ formed Al4SiC4 reinforcing phase, both the strip- and particle-structured Al4SiC4, increased markedly. The significant grain coarsening and the formation of the interfacial microscopic shrinkage porosity lowered the mechanical properties of the SLM-processed Al-based composites. These findings in the present work are applicable and/or transferrable to other laser-based powder processing processes, e.g., laser cladding, laser metal deposition, or laser engineered net shaping.

Microstructure and mechanical property of selective laser melted Ti6Al4V dependence on laser energy density

2017 ◽  
Vol 23 (2) ◽  
pp. 217-226 ◽  
Author(s):  
Jie Han ◽  
Jingjing Yang ◽  
Hanchen Yu ◽  
Jie Yin ◽  
Ming Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Density ◽  
Laser Energy ◽  
Ti6al4v Alloy ◽  
Laser Energy Density ◽  
Future Application ◽  
Content Type ◽  
Processing Window ◽  
Columnar Grains ◽  
Columnar Grain

Purpose This paper aims to investigate the influence of laser energy density on microstructure and mechanical properties of the selective laser melted (SLMed) Ti6Al4V to complement the existing knowledge in additive manufacturing of Ti6Al4V for future application of selective laser melting (SLM) in fabricating Ti6Al4V parts. Design/methodology/approach Ti6Al4V alloy is fabricated by SLM by adopting various energy densities. Microstructures and mechanical properties of the Ti6Al4V deposited using different energy densities are characterized. Findings Both high relative densities and microhardness can be obtained in the optimized processing window. The decrease of martensite width and spacing can improve the microhardness on both XOY and XOZ sections when the applied EV (defined as the laser energy per unit volume) increases. The width of the columnar grain increases with EV, resulting in a stronger anisotropy in microhardness between XOY and XOZ sections. Residual tensile stresses exist in the SLMed Ti6Al4V and increase with an increasing EV. A tensile strength of 1,268 MPa, a yield strength of 1,030 MPa, and an elongation of 4% can be obtained by using the optimized range of EV. Originality/value The microstructure of SLMed Ti6Al4V is quantitatively analysed by measuring the size of columnar grains and the martensites. The anisotropy of microstructures and properties in SLMed Ti6Al4V is characterized and its dependence on laser energy density is established. The residual stress in SLMed Ti6Al4V is characterized and its dependence on laser energy density is established. An optimized processing window to deposit Ti6Al4V alloy by SLM is proposed.

scholarly journals Effect of Laser Energy Density, Internal Porosity and Heat Treatment on Mechanical Behavior of Biomedical Ti6Al4V Alloy Obtained with DMLS Technology

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2331 ◽  
Author(s):  
Żaneta Anna Mierzejewska
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Energy Density ◽  
Laser Energy ◽  
Xrd Analysis ◽  
Laser Energy Density ◽  
Simultaneous Increase ◽  
Direct Metal Laser Sintering ◽  
X Ray Diffraction ◽  
Elongation At Break

The purpose of this paper was to determine the influence of selected parameters of Direct Metal Laser Sintering and various heat treatment temperatures on the mechanical properties of Ti6Al4V samples oriented vertically (V, ZX) and horizontally (H, XZ). The performed micro-CT scans of as-build samples revealed that the change in laser energy density significantly influences the change in porosity of the material, which the parameters (130–210 W; 300–1300 mm/s), from 9.31% (130 W, 1300 mm/s) to 0.16% (190 W, 500 mm/s) are given. The mechanical properties, ultimate tensile strength (UTS, Rm) and yield strength (YS, Re) of the DMLS as-build samples, were higher than the ASTM F 1472 standard suggestion (UTS = 1100.13 ± 126.17 MPa, YS = 1065.46 ± 127.91 MPa), and simultaneously, the elongation at break was lower than required for biomedical implants (A = 4.23 ± 1.24%). The low ductility and high UTS were caused by a specific microstructure made of α’ martensite and columnar prior β grains. X-Ray Diffraction (XRD) analysis revealed that heat treatment at 850 °C for 2 h caused the change of the microstructure intothe α + β combination, affecting the change of strength parameters—a reduction of UTS and YS with the simultaneous increase in elongation (A). Thus, properties similar to those indicated by the standard were obtained (UTS = 908.63 ± 119.49 MPa, YS = 795.9 ± 159.32 MPa, A = 8.72 ± 2.51%), while the porosity remained almost unchanged. Moreover, the heat treatment at 850 °C resulted in the disappearance of anisotropic material properties caused by the layered structure (UTSZX = 908.36 ± 122.79 MPa, UTSXZ = 908.97 ± 118.198 MPa, YSZX = 807.83 ± 124.05 MPa, YSXZ = 810.56 ± 124.05 MPa, AZX = 8.75 ± 2.65%, and AXZ = 8.68 ± 2.41%).

scholarly journals Influence of Effective Laser Energy on the Structure and Mechanical Properties of Laser Melting Deposited Ti6Al4V Alloy

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 962 ◽  
Author(s):  
Daojian Fu ◽  
Xiaoqiang Li ◽  
Minai Zhang ◽  
Min Wang ◽  
Zhen Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Density ◽  
Laser Energy ◽  
Ti6al4v Alloy ◽  
Laser Energy Density ◽  
Coefficient Of Determination ◽  
Structure Property ◽  
Laser Melting ◽  
Process Structure ◽  
Am Processes

The laser energy density (ED) is often utilized in many additive manufacturing (AM) processes studies to help researchers to further investigate the process-structure-property correlations of Ti6Al4V alloys. However, the reliability of the ED is still questionable. In this work, a specific empirical calculation equation of the effective laser energy (Ee), which is a dimensionless parameter in laser melting deposition (LMD) processing, was proposed based on the molten pool temperature. The linear regression results and the coefficient of determination prove the feasibility of the Ee equation, which indicates that Ee can more accurately reflect the energy-temperature correlations than the commonly used laser energy density (ED) equation. Additionally, Ti6Al4V components were fabricated by the LMD process with different Ee to investigate the influence of Ee on their structure and mechanical properties. Experimental results show that the detrimental columnar prior β meso-structure can be circumvented and the uniform α + β laths micro-structure can be obtained in LMD Ti6Al4V by a judicious combination of the process parameter (P = 2000 W, V = 12 mm/s, and F = 10.5 g/min) and Ee (7.98 × 105) with excellent tensile strength (1006 ± 25 MPa) and elongation (14.9 ± 0.6%). Overall, the present work provides an empirical calculation equation to obtain a clearer understanding of the influence of different process parameters and indicates the possibility to fabricate the Ti6Al4V alloy with excellent mechanical properties by parameter optimization in the LMD process.

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