scholarly journals Analysis of Microstructure and Mechanical Properties in As-Built/As-Cast and Heat-Treated Conditions for IN718 Alloy Obtained by Selective Laser Melting and Investment Casting Processes

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1196
Author(s):  
Juan Carlos Pereira ◽  
Jon Aranzabe ◽  
Mari Carmen Taboada ◽  
Noelia Ruiz ◽  
Pedro Pablo Rodriguez

In this work, new customized heat treatments for selective laser melted (SLM) parts in IN718 alloy were analyzed. This was done through the evaluation of the mechanical properties and advanced characterization of the phases and microstructure obtained in as-built condition and after the application of standard and tailored heat treatments. The microstructure and mechanical properties were compared and discussed with results reported in the literature. Finally, strengthening mechanisms of IN718 alloy processed by SLM and its differences with mechanisms that occur in investment casting were analyzed. Both processes generate quite different microstructures, investment casting is composed mainly by a dendritic structure, and SLM is characterized by columnar and cellular structures with very thin cells. Due to the fine and homogeneous microstructure obtained from SLM processing and its specific strengthening mechanisms, it is not necessary to apply homogenization and solution stages as in standard heat treatment used for this type of alloy in casting or wrought. The pre-heating and process parameters selected, in combination with a direct stepped aging (at 720 °C/620 °C), provide the material with its best mechanical properties, which are superior to those obtained by standard heat treatment (AMS 5383F) applied to investment casting of IN718 alloy.

2018 ◽  
Vol 284 ◽  
pp. 615-620 ◽  
Author(s):  
R.M. Baitimerov ◽  
P.A. Lykov ◽  
L.V. Radionova

TiAl6V4 titanium base alloy is widely used in aerospace and medical industries. Specimens for tensile tests from TiAl6V4 with porosity less than 0.5% was fabricated by selective laser melting (SLM). Specimens were treated using two heat treatment procedures, third batch of specimens was tested in as-fabricated statement after machining. Tensile tests were carried out at room temperature. Microstructure and mechanical properties of SLM fabricated TiAl6V4 after different heat treatments were investigated.


2017 ◽  
Vol 898 ◽  
pp. 476-479
Author(s):  
Jin Xia Yang ◽  
Yuan Sun ◽  
Dong Ling Zhou

The effects of HIP process on microstructure and mechanical properties of IN792 cast superalloy were studied. The results showed that HIP process produced more uniform and finer cubic γ′ than standard heat treatment. The difference of the mechanical properties should be caused by the microstructure changes. HIP process leads the homogeneous distribution of γ′ at dendritic arm and interdendritic area, and improved UTS and YS of tested alloy at 550°C. However, it played no role in increasing UTS and YS at room temperature and stress-rupture lives of 760°C/662MPa and decreased stress-rupture lives of 982°C/186MPa.


This work is a part of research on the microstructure and mechanical properties of Cr-Mn-Si steels after various thermal treatments. In order to increase the resistance of the materials against failure it is necessary to possess simultaneously high strength and plasticity at the same time. Normally, in conventional metals, this is impossible. The purpose of the present study is to trace the polymorphic transformation of the microstructure and the redistribution of the trace elements in the corresponding microstructural transformations of the steel at each stage of applied heat treatment - austenization, quenching, austempering, tempering. The chosen sequence of applied heat treatments is to obtain a bainite structure of up to 50% in order to achieve high strength and toughness of the material.


2012 ◽  
Vol 452-453 ◽  
pp. 31-34
Author(s):  
Xuan Xiao ◽  
Zeng Chao ◽  
Xu Le ◽  
Li Yuan Sheng ◽  
Yong An Guo ◽  
...  

In order to figure out whether Gallium works in the superalloy K444, its composition had been modified by adding about 0.003 wt.% and 0.01 wt.% Ga, respectively. Mechanical properties of the modified superalloy K444 were investigated by using scanning electron microscopy (SEM) after standard heat treatment. Gallium had no significant effect on the tensile strength at room temperature and 900 °C. Gallium had a little effect on the tensile plasticity at room temperature and 900 °C. The plasticity is better in the modified K444 alloy containing 0.003wt. % Ga, however, the plasticity became worse in the alloy containing 0.01wt. % Ga. As for plasticity, the optimum Gallium content should be 0.003 wt. % for the superalloy K444.


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