Outlooks in laser work hardening for characteristics increase of parts obtained by selective laser melting

2018 ◽  
Vol 2018 (7) ◽  
pp. 32-37
Author(s):  
Д. Мельников ◽  
D. Melnikov ◽  
Е. Калёнова ◽  
E. Kalyonova ◽  
Зо Зо Йе Мьят ◽  
...  
Keyword(s):  
Surface Layer ◽  
Selective Laser Melting ◽  
Work Hardening ◽  
Shock Treatment ◽  
Fatigue Properties ◽  
Laser Shock ◽  
Laser Melting ◽  
Near Surface ◽  
Hybrid Technology ◽  
Laser Shock Treatment

The paper deals with the development of a new hybrid technology – 3D laser work hardening which consists in the integration of laser shock treatment (laser work hardening) into the process of selective laser melting. The technology offered will allow obtaining an area of compressing residual stresses in a near surface layer and achieving the improvement of mechanical and fatigue properties of parts manufactured. In this paper the aluminum alloy samples were processed with laser work hardening with the use of uncommon absorbing and transparent layers (foil and glass) which are necessary for the introduction selective laser melting in a plant. Modes of laser work hardening were also investigated which may be used in the hybrid technology offered.

scholarly journals Selective Laser Melting of Aluminum and Its Alloys

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4564 ◽  
Author(s):  
Zhi Wang ◽  
Raghunandan Ummethala ◽  
Neera Singh ◽  
Shengyang Tang ◽  
Challapalli Suryanarayana ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Processing Parameters ◽  
Fatigue Properties ◽  
Internal Stresses ◽  
Surface Oxide Layer ◽  
Alloy Development ◽  
Laser Melting ◽  
Powder Bed ◽  
Microstructure Evaluation ◽  
Melt Cooling

The laser-based powder bed fusion (LBPF) process or commonly known as selective laser melting (SLM) has made significant progress since its inception. Initially, conventional materials like 316L, Ti6Al4V, and IN-718 were fabricated using the SLM process. However, it was inevitable to explore the possible fabrication of the second most popular structural material after Fe-based alloys/steel, the Al-based alloys by SLM. Al-based alloys exhibit some inherent difficulties due to the following factors: the presence of surface oxide layer, solidification cracking during melt cooling, high reflectivity from the surface, high thermal conductivity of the metal, poor flowability of the powder, low melting temperature, etc. Researchers have overcome these difficulties to successfully fabricate the different Al-based alloys by SLM. However, there exists no review dealing with the fabrication of different Al-based alloys by SLM, their fabrication issues, microstructure, and their correlation with properties in detail. Hence, the present review attempts to introduce the SLM process followed by a detailed discussion about the processing parameters that form the core of the alloy development process. This is followed by the current research status on the processing of Al-based alloys and microstructure evaluation (including defects, internal stresses, etc.), which are dealt with on the basis of individual Al-based series. The mechanical properties of these alloys are discussed in detail followed by the other important properties like tribological properties, fatigue properties, etc. Lastly, an outlook is given at the end of this review.

scholarly journals Corrosion Behavior of NiTi Alloys Fabricate by Selective Laser Melting Subjected to Femtosecond Laser Shock Peening

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1078
Author(s):  
Long Ma ◽  
Wanqing Li ◽  
Yongzhi Yang ◽  
Yuanxue Ma ◽  
Kai Luo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Femtosecond Laser ◽  
Selective Laser Melting ◽  
Niti Alloy ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Laser Melting ◽  
Corrosion Failure ◽  
Niti Alloys ◽  
Shock Peening

NiTi alloys are commonly used in many fields such as aerospace, mechanical engineering due to their excellent mechanical properties and shape memory effect. In recent years, the emergence of selective laser melting (SLM) technology provides a new method for the preparation of NiTi parts. But the surface corrosion failure of SLM-NiTi is the most common problem. This paper mainly focuses on the research of femtosecond laser shock peening of the surface of SLM-NiTi alloy to improve the corrosion resistance. Selecting different scanning space (1 μm, 3 μm, 5 μm, 10 μm), and analyze the surface morphology of the material through the OM, SEM, EDS and white light interferometer, and investigate the surface nanohardness and corrosion resistance through nanoindentation and electrochemical testing. The research results show that part of the TiO2 is formed under different scanning spaces, and part of NiO is formed when the scanning space is 1μm. At the same time, it is found that the sample under the condition of 10 μm has the most excellent corrosion resistance and nanohardness. The nanohardness reaches 1303 ± 40 HV and the corrosion current density reaches 1.45 ± 0.1 × 10−9 A·cm−2. Proper femtosecond laser treatment can effectively improve the surface strength and corrosion resistance of the NiTi alloys.

Low-Cycle-Fatigue Properties of a 17-4 PH Stainless Steel Manufactured via Selective Laser Melting

2021 ◽  
Vol 877 ◽  
pp. 55-60
Author(s):  
Lorenzo Maccioni ◽  
Eleonora Rampazzo ◽  
Filippo Nalli ◽  
Yuri Borgianni ◽  
Franco Concli
Keyword(s):  
Stainless Steel ◽  
Selective Laser Melting ◽  
Low Cycle Fatigue ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Laser Melting ◽  
Softening Behavior ◽  
The One ◽  
Cylindrical Samples

In this paper, the static and low-cycle-fatigue (LCF) behavior of wrought samples of 17-4 PH stainless steel (SS) manufactured via Selective Laser Melting (SLM) are presented. On the one hand, several scholars have studied SLM materials and literature reports a huge amount of data as for the high-cycle-fatigue (HCF) behavior. On the other hand, few are the data available on the LCF behavior of those materials. The aim of the present research is to provide reliable data for an as-build 17-4 PH steel manufactured via SLM techniques. Only with quantitative data, indeed, it is possible to exploit all the advantages that this technology can offer. In this regard, both quasi-static (QS) and low-cycle-fatigue tests were performed on Additive Manufacturing (AM) cylindrical samples. Through QS tests, the constitutive low has been defined. Strain-controlled fatigue tests on an electromechanical machine were performed on 12 samples designed according to the ASTM standard. Tests were continued also after the stabilization was reached (needed for the cyclic curve described with the Ramberg-Osgood equation) to obtain also the fatigue (ε-N) curve. Results show that the material has a softening behavior. The Basquin-Coffin-Manson (BCM) parameters were tuned on the basis of the ε-N combinations after rupture.

Sign in / Sign up

Export Citation Format

Share Document