scholarly journals Effects of the γ″-Ni3Nb Phase on Mechanical Properties of Inconel 718 Superalloys with Different Heat Treatments

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 151
Author(s):  
Li-Shi-Bao Ling ◽  
Zheng Yin ◽  
Zhi Hu ◽  
Jin-Hui Liang ◽  
Zhi-Yong Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Inconel 718 ◽  
Hot Isostatic Pressing ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Strengthening Mechanism ◽  
Morphological Observation ◽  
Isostatic Pressing ◽  
Direct Aging

The effects of the γ″-Ni3Nb phase on the mechanical properties of Inconel 718 superalloys, with standard heat treatment, hot isostatic pressing + solution treatment + aging, and hot isostatic pressing + direct aging, were characterized by morphological observation, X-ray diffraction, and tensile experiments. The results of the morphological observation revealed that many fine γ″ precipitates of ~26.49 ± 1.82 nm in mean size were formed in all samples. However, the relatively coarser γ″ precipitates formed in the grain boundaries were only observed in the sample treated with hot isostatic pressing + direct aging. The yield strengths of the hot isostatic pressing + direct aging sample at room temperature and at 650 °C both exhibited the maximum values about 993 ± 5.7 and 811 ± 12.6 MPa, respectively. The γ″ precipitate was considered to be the dominant strengthening phase in the sample according to the lattice misfits (ε) of γ/γ″. The strengthening mechanism of the samples can be explained as the coherency strain strengthening of fine γ″ precipitates. Moreover, due to the coarser γ″ precipitates in the grain boundaries, dislocation-cut ordered particle strengthening also occurred in the sample after hot isostatic pressing + direct aging treatment.

scholarly journals Effects of the γ″-Ni3Nb Phase on Fatigue Behavior of Nickel-Based 718 Superalloys with Different Heat Treatments

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3979 ◽  
Author(s):  
Li-Shi-Bao Ling ◽  
Zheng Yin ◽  
Zhi Hu ◽  
Jun Wang ◽  
Bao-De Sun
Keyword(s):  
Heat Treatment ◽  
Grain Boundaries ◽  
Fatigue Behavior ◽  
Hot Isostatic Pressing ◽  
Solution Treatment ◽  
Standard Heat Treatment ◽  
Isostatic Pressing ◽  
Standard Heat ◽  
Direct Aging ◽  
The Matrix

The effects of the γ″-Ni3Nb phase on fatigue behavior of nickel-based 718 superalloys with standard heat treatment, hot isostatic pressing + solution treatment + aging, and hot isostatic pressing + direct aging were investigated by scanning electron microscope, transmission electron microscopy, and fatigue experiments. The standard heat treatment, hot isostatic pressing + solution treatment + aging, and hot isostatic pressing + direct aging resulted in the formation of more and smaller γ″ phases in the matrix in the nickel-based 718 superalloys. However, the grain boundaries of the hot isostatic pressing + direct aging sample showed many relatively coarse disk-like γ″ phases with major axes of ~80 nm and minor axes of ~40 nm. The hot isostatic pressing + direct aging sample with a stress amplitude of 380 MPa showed the longest high cycle fatigue life of 5.16 × 105 cycles. Laves phases and carbide inclusions were observed in the crack initiation zone, and the cracks propagated along the acicular δ phases in the nickel-based 718 superalloys. The precipitation of fine γ″ phases in the matrix and relatively coarse γ″ phases in the grain boundaries of the hot isostatic pressing + direct aging sample can hinder the movement of dislocation.

scholarly journals Enhancing Mechanical Properties of the Spark Plasma Sintered Inconel 718 Alloy by Controlling the Nano-Scale Precipitations

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3336
Author(s):  
Shuaijiang Yan ◽  
Yun Wang ◽  
Qingxiang Wang ◽  
Chengsong Zhang ◽  
Dazhi Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Inconel 718 ◽  
Production Efficiency ◽  
Solution Treatment ◽  
Inconel 718 Alloy ◽  
Direct Aging ◽  
Spark Plasma

The present study aimed to optimize the phase constituents and mechanical properties of the spark plasma sintered (SPS) Inconel 718 (IN718) alloy. A series of heat treatment routes were designed based on the phase relations in IN718 and performed for the optimization. The microstructure and phase compositions of the SPS IN718 alloys were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), and transmission electron microscopy (TEM). The mechanical properties of the samples were characterized at room temperature and at 650 °C. The results showed that large amounts of γ” (Ni3Nb) and γ’ (Ni3(Al, Ti)) strengthening phases precipitated in the IN718 alloy after direct aging (DA) of the as-fabricated sample. Moreover, the mechanical properties of the DA sample were comparable to that of the best one of the solution-treated and aged counterparts. The analysis showed that the rapid sintering and solid solution treatment of the IN718 alloy were achieved simultaneously by SPS. In the case of the SPS IN718 material, the direct aging regime had the same heat treatment effect as the conventional solid solution and aging treatment. This contributes toward improving the production efficiency and reduces manufacturing costs in the actual production process.

scholarly journals Effect of hot isostatic pressing on the microstructure of turbine blade airfoil made of nickel-base superalloy

2017 ◽  
Vol 62 (1) ◽  
pp. 241-245
Author(s):  
B. Chmiela ◽  
B. Kościelniak ◽  
J. Cwajna
Keyword(s):  
Mechanical Properties ◽  
Structural Changes ◽  
Diffusion Processes ◽  
Electron Backscatter Diffraction ◽  
Turbine Blades ◽  
Hot Isostatic Pressing ◽  
Solution Treatment ◽  
Leading Edge ◽  
Nickel Base Superalloy ◽  
Isostatic Pressing

Abstract Turbine blades are flight safety parts in the jet engine. Therefore they should be characterized by very good mechanical properties, especially high creep resistance and fatigue strength at high temperature. The mechanical properties of blades made of nickel-based superalloys depend on the microstructure of the casting and its porosity [1,2]. The aim of this paper is evaluation of effect of hot isostatic pressing (HIP) on microstructure of blade airfoil made of IN713C superalloy in four important zones: (i) leading edge, (ii) trailing edge, (iii) suction side and (iv) pressure side. HIP treatment was carried out proving some significant microstructural changes. Electron backscatter diffraction (EBSD) analysis reveals some structural changes what may facilitate diffusion processes leading to simplify of a heat treatment (solution treatment and aging).

Microstructures and Mechanical Properties of Nano-Composite Ti(C,N)-Based Cermets

2007 ◽  
Vol 336-338 ◽  
pp. 1214-1217
Author(s):  
Wen Jun Liu ◽  
Yong Zheng ◽  
Wei Hao Xiong
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Hot Isostatic Pressing ◽  
Nano Particles ◽  
Vacuum Sintering ◽  
Nano Composite ◽  
Isostatic Pressing ◽  
Nano Powder ◽  
Heat Treated ◽  
Small Grains

Several nano-composite Ti(C, N)-based cermets were produced by vacuum sintering and subsequently heat-treated with hot isostatic pressing (HIP) in Ar. The influence of nano powder additions on the microstructures and properties of cermets has been studied It was found that, with increasing nano powder additions, the microstructures became finer and even, the amount of small grains with inner-rim, outer-rim and those with “white core-gray rim” increased. When nano TiC and TiN additions accounted for 20wt% of the amount of TiC and TiN, the samples exhibited the best properties. Some nano particles were found to distribute at (along?) the grain boundaries of cermets, which strengthened the grain boundaries and improved the mechanical properties of Ti(C, N)-based cermets.

The Investigation on Aluminium Alloys Automobile Wheel with Low-Titanium Content Produced by Electrolysis

2005 ◽  
Vol 475-479 ◽  
pp. 317-320 ◽  
Author(s):  
Jing Pei Xie ◽  
Ji Wen Li ◽  
Zhong Xia Liu ◽  
Ai Qin Wang ◽  
Yong Gang Weng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminium Alloys ◽  
Solution Treatment ◽  
A356 Alloy ◽  
Aging Treatment ◽  
Titanium Content ◽  
The Matrix ◽  
Automobile Wheel

The in-situ Ti alloying of aluminium alloys was fulfilled by electrolysis, and the material was made into A356 alloy and used in automobile wheels. The results show that the grains of the A356 alloy was refined and the second dendrites arm was shortened due to the in-situ Ti alloying. Trough 3-hour solution treatment and 2-hour aging treatment for the A356 alloy, the microstructures were homogeneous, and Si particles were spheroid and distribute in the matrix fully. The outstanding mechanical properties with tensile strength (σb≥300Mpa) and elongation values (δ≥10%) have been obtained because the heat treatment was optimized. Compared with the traditional materials, tensile strength and elongation were increased by 7.6~14.1% and 7.4~44.3% respectively. The qualities of the automobile wheels were improved remarkably.

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