scholarly journals Improvement on mechanical properties and corrosion resistance of titanium-tantalum alloys in-situ fabricated via selective laser melting

2019 ◽  
Vol 804 ◽  
pp. 288-298 ◽  
Author(s):  
Danlei Zhao ◽  
Changjun Han ◽  
Yan Li ◽  
Jingjing Li ◽  
Kun Zhou ◽  
...  
Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1012 ◽  
Author(s):  
Feng Shang ◽  
Xiaoqiu Chen ◽  
Zhiyong Wang ◽  
Zuchun Ji ◽  
Fei Ming ◽  
...  

UNS S32707 hyper-duplex stainless steel (HDSS) parts with complex shapes for ocean engineering were prepared by selective laser melting (SLM) process. In the process of SLM, the balance between austenite and ferrite was undermined due to the high melting temperature and rapid cooling rate, resulting in poor ductility and toughness. The solution annealing was carried out with various temperatures (1050–1200 °C) for one hour at a time. The evolution of microstructures, mechanical properties, and corrosion resistance of UNS S32707 samples prepared by SLM was comprehensively investigated. The results indicate that a decrease in nitrogen content during the SLM process reduced the content of austenite, and a nearly balanced microstructure was obtained after appropriate solution annealing. The ratio between ferrite and austenite was approximately 59.5:40.5. The samples with solution treated at 1150 °C and 1100 °C exhibited better comprehensive mechanical properties and pitting resistance, respectively.


Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2468 ◽  
Author(s):  
Papula ◽  
Song ◽  
Pateras ◽  
Chen ◽  
Brandt ◽  
...  

Additive manufacturing (AM) is a rapidly growing field of technology. In order to increase the variety of metal alloys applicable for AM, selective laser melting (SLM) of duplex stainless steel 2205 powder and the resulting microstructure, density, mechanical properties, and corrosion resistance were investigated. An optimal set of processing parameters for producing high density (>99.9%) material was established. Various post-processing heat treatments were applied on the as-built predominantly ferritic material to achieve the desired dual-phase microstructure. Effects of annealing at temperatures of 950 °C, 1000 °C, 1050 °C, and 1100 °C on microstructure, crystallographic texture, and phase balance were examined. As a result of annealing, 40–46 vol.% of austenite phase was formed. Annealing decreased the high yield and tensile strength values of the as-built material, but significantly increased the ductility. Annealing also decreased the residual stresses in the material. Mechanical properties of the SLM-processed and heat-treated materials outperformed those of conventionally produced alloy counterparts. Using a scanning strategy with 66° rotation between layers decreased the strength of the crystallographic texture. Electrochemical cyclic potentiodynamic polarization testing in 0.6 M NaCl solution at room temperature showed that the heat treatment improved the pitting corrosion resistance of the as-built SLM-processed material.


Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1121 ◽  
Author(s):  
Li ◽  
Liang ◽  
Tian ◽  
Yang ◽  
Xie ◽  
...  

Titanium composite strengthened by Ti3Al precipitations is considered to be one of the excellent materials that is widely used in engineering. In this work, we prepared a kind of Ti-Ti3Al metallic composite by in-situ synthesis technology during the SLM (selective laser melting) process, and analyzed its microstructure, wear resistance, microhardness, and compression properties. The results showed that the Ti-Ti3Al composite, prepared by in-situ synthesis technology based on SLM, had more homogeneous Ti3Al-enhanced phase dispersion strengthening structure. The grain size of the workpiece was about 1 μm, and that of the Ti3Al particle was about 200 nm. Granular Ti3Al was precipitated after the aluminum-containing workpiece formed, with a relatively uniform distribution. Regarding the mechanical properties, the hardness (539 HV) and the wear resistance were significantly improved when compared with the Cp-Ti workpiece. The compressive strength of the workpiece increased from 886.32 MPa to 1568 MPa, and the tensile strength of the workpiece increased from 531 MPa to 567 MPa after adding aluminum. In the future, the combination of in-situ synthesis technology and SLM technology can be used to flexibly adjust the properties of Ti-based materials.


Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 629
Author(s):  
Anagh Deshpande ◽  
Subrata Deb Nath ◽  
Sundar Atre ◽  
Keng Hsu

Selective laser melting (SLM) is one of the most widely used additive manufacturing technologies. Fabricating nickel-based superalloys with SLM has garnered significant interest from the industry and the research community alike due to the excellent high temperature properties and thermal stability exhibited by the alloys. Haynes-282 alloy, a γ′-phase strengthened Ni-based superalloy, has shown good high temperature mechanical properties comparable to alloys like R-41, Waspaloy, and 263 alloy but with better fabricability. A study and comparison of the effect of different heat-treatment routes on microstructure and mechanical property evolution of Haynes-282 fabricated with SLM is lacking in the literature. Hence, in this manuscript, a thorough investigation of microstructure and mechanical properties after a three-step heat treatment and hot isostatic pressing (HIP) has been conducted. In-situ heat-treatment experiments were conducted in a transmission electron microscopy (TEM) to study γ′ precipitate evolution. γ′ precipitation was found to start at 950 °C during in-situ heat-treatment. Insights from the in-situ heat-treatment were used to decide the aging heat-treatment for the alloy. The three-step heat-treatment was found to increase yield strength (YS) and ultimate tensile strength (UTS). HIP process enabled γ′ precipitation and recrystallization of grains of the as-printed samples in one single step.


NANO ◽  
2021 ◽  
Author(s):  
Qingxia Zhang ◽  
Lingtao Meng ◽  
Xiaotian Yin ◽  
Shenghai Wang ◽  
Yong Liu ◽  
...  

In previous studies, the microstructure, mechanical properties and corrosion resistance of Hastelloy X fabricated by selective laser melting (SLM) have been investigated; however, it is hoped that heat treatment will effect on its properties. Therefore, this study is to discuss heat treatment effect on Hastelloy X fabricated by SLM. It is interestingly found that fracture strain greatly increases with heat treatment, and the yield ratio decreases, which demonstrates the material is more reliable. High temperature tensile behavior is discussed; it is worth mentioning that not only fracture strain of the HT sample increases greatly at 550∘C in comparison with SLM sample, but also ultimate tensile strength increases from 632 MPa to 639 MPa; the results show that the mechanical property can be improved at medium and high temperature by heat treatment. The corrosion resistance of HT sample deteriorates slightly, which can be explained by Cr-rich precipitates. In conclusion, the material after heat treatment is suitable for applications requiring high mechanical reliability and medium and high temperature occasions, but it is not befitting for corrosive environments.


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