scholarly journals The Formation of 14H-LPSO in Mg–9Gd–2Y–2Zn–0.5Zr Alloy during Heat Treatment

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5758
Author(s):  
Yunfang Liu ◽  
Yaqin Yang ◽  
Ming Yi ◽  
Jianmin Yu ◽  
Baocheng Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Grain Size ◽  
Volume Fraction ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Phase Changes ◽  
Solution Temperature ◽  
Second Phase ◽  
Lpso Phase

There is a new long-period stacking ordered structure in Mg–RE–Zn magnesium alloys, namely the LPSO phase, which can effectively improve the yield strength, elongation, and corrosion resistance of Mg alloys. According to different types of Mg–RE–Zn alloy systems, two transformation modes are involved in the heat treatment transformation process. The first is the alloy without LPSO phase in the as-cast alloy, and the MgxRE phase changes to 14H-LPSO phase. The second is the alloy containing LPSO phase in the as-cast state, and the 14H-LPSO phase is obtained by the transformations of 6H, 18R, and 24R. The effects of different solution parameters on the second phase of Mg–9Gd–2Y–2Zn–0.5Zr alloy were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The precipitation mechanism of 14H-LPSO phase during solution treatment was further clarified. At a solution time of 13 h, the grain size increased rapidly initially and then decreased slightly with increasing solution temperature. The analysis of the volume fraction of the second phase and lattice constant showed that Gd and Y elements in the alloy precipitated from the matrix and formed 14H-LPSO phase after solution treatment at 490 °C for 13 h. At this time, the hardness of the alloy reached the maximum of 74.6 HV. After solution treatment at 500 °C for 13 h, the solid solution degree of the alloy increases, and the grain size and hardness of the alloy remain basically unchanged.

scholarly journals The Effect of Heat Treatment on the Microstructure and Mechanical Properties of the Novel Low-Cost Ti-3Al-5Mo-4Cr-2Zr-1Fe Alloy

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3798
Author(s):  
Meng Sun ◽  
Dong Li ◽  
Yanhua Guo ◽  
Ying Wang ◽  
Yuecheng Dong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aging Time ◽  
Volume Fraction ◽  
Low Cost ◽  
Solution Treatment ◽  
Solution Temperature ◽  
The Novel ◽  
Α Phase ◽  
The Cost

In order to reduce the cost of titanium alloys, a novel low-cost Ti-3Al-5Mo-4Cr-2Zr-1Fe (Ti-35421) titanium alloy was developed. The influence of heat treatment on the microstructure characteristics and mechanical properties of the new alloy was investigated. The results showed that the microstructure of Ti-35421 alloy consists of a lamina primary α phase and a β phase after the solution treatment at the α + β region. After aging treatment, the secondary α phase precipitates in the β matrix. The precipitation of the secondary α phase is closely related to heat treatment parameters—the volume fraction and size of the secondary α phase increase when increasing the solution temperature or aging time. At the same solution temperature and aging time, the secondary α phase became coarser, and the fraction decreased with increasing aging temperature. When Ti-35421 alloy was solution-treated at the α + β region for 1 h with aging surpassing 8 h, the tensile strength, yield strength, elongation and reduction of the area were achieved in a range of 1172.7–1459.0 MPa, 1135.1–1355.5 MPa, 5.2–11.8%, and 7.5–32.5%, respectively. The novel low-cost Ti-35421 alloy maintains mechanical properties and reduces the cost of materials compared with Ti-3Al-5Mo-5V-4Cr-2Zr (Ti-B19) alloy.

Effect of Nd Content and Heat Treatment on Microstructure and Mechanical Properties of Mg-Zn-Nd Alloy

2017 ◽  
Vol 898 ◽  
pp. 124-130 ◽  
Author(s):  
Shu Min Xu ◽  
Xin Ying Teng ◽  
Xing Jing Ge ◽  
Jin Yang Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Cast Alloy ◽  
Second Phase ◽  
Casting Method ◽  
Magnesium Matrix ◽  
Microstructure And Mechanical Properties

In this paper, the microstructure and mechanical properties of the as-cast and heat treatment of Mg-Zn-Nd alloy was investigated. The alloy was manufactured by a conventional casting method, and then subjected to a heat treatment. The results showed that the microstructure of as-cast alloy was comprised of α-Mg matrix and Mg12Nd phase. With increase of Nd content, the grain size gradually decreased from 25.38 μm to 9.82 μm. The ultimate tensile strength and elongation at room temperature of the Mg94Zn2Nd4 alloy can be reached to 219.63 MPa and 5.31%. After heat treatment, part of the second phase dissolved into the magnesium matrix and the grain size became a little larger than that of the as-cast. The ultimate tensile strength was declined by about 2.5%, and the elongation was increased to 5.47%.

scholarly journals Study of the precipitation hardening process in recycled Al-Si-Cu cast alloys

2017 ◽  
Vol 62 (1) ◽  
pp. 397-403 ◽  
Author(s):  
L. Kuchariková ◽  
E. Tillová ◽  
M. Matvija ◽  
J. Belan ◽  
M. Chalupová
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Precipitation Hardening ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Second Phase ◽  
Thin Foils ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Cast Alloys

AbstractThe formation of extremely small uniformly dispersed particles of a second phase within the original phase matrix during heat treatment changed material properties. Therefore the characterization of precipitation had been investigated using high resolution transmission electron microscopy (TEM) and electron diffraction of thin foils for an AlSi9Cu3 cast alloy. For investigation the hardening effect onto mechanical properties of aluminium cast was used heat treatment, which consisted from solution treatment at 515°C / 4 hours (h), followed by quenching into water with temperature 50°C and artificial aging using different temperatures 170°C and 190°C with different holding time 2, 4, 8, 16, and 32 hours. The observations of microstructure and substructure reveals that precipitation hardening has caused great changes in size, morphology and distributions of structural components, the formation of precipitates of Cu phases, and the change of mechanical properties as well.

Effects of Heat Treatment on Microstructure and Properties of AZ91D Magnesium Alloy

2013 ◽  
Vol 575-576 ◽  
pp. 410-413
Author(s):  
Ming Wu ◽  
Fang Long ◽  
Hao Ran Geng ◽  
Fang Yang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Test ◽  
Artificial Aging ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Second Phase ◽  
Az91d Alloy ◽  
Az91d Magnesium Alloy ◽  
Heat Treated

The microstructure, hardness and corrosion resistance of AZ91D alloy were investigated under different solution treatments and artificial aging conditions.When ascast AZ91D alloy was heat treated at 415°C by solution treatmentfor 12 h and artificially aged at 200°C, the volume fraction of precipitates increased with the aging time up to 10 h.When ascast AZ91D alloy was treated at 430°C by solution treatment for 12 h and artificially aged at 200°C for 10h, the volume fraction of precipitates reached a peak value.The results of the corrosion test showed that a high corrosion resisting of the second phase precipitates was beneficial to improving the strength and hardness. Solution treatment at 445°C temperature for 12 h destroied the consecutiveness of β-Mg17Al12 phases.

Effect of Sm on the Microstructure and Mechanical Property of Mg-xSm-0.4Zn-0.3Zr Alloys

2013 ◽  
Vol 747-748 ◽  
pp. 238-244 ◽  
Author(s):  
Xin Su ◽  
De Jiang Li ◽  
Yan Cai Xie ◽  
Xiao Qin Zeng ◽  
Wen Jiang Ding
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Volume Fraction ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Age Hardening ◽  
Second Phase ◽  
Gravity Casting ◽  
Cast Alloys ◽  
Microstructure And Mechanical Property

The effect of Sm content (2, 4, 6, 8wt.%) on the microstructures and mechanic properties of gravity casting Mg-xSm-0.4Zn-0.3Zr alloys were investigated. The results showed that the cast alloy mainly consists of α-Mg matrix and Mg41Sm5 phase distributed at the grain boundaries, and the amount of the second phase increased with the rise of Sm content. After the solution treatment (T4), the second phase disappeared, however small amount of cuboid-like phase were found inside the grain, and its volume fraction also increases with the rise of Sm content. It is found in the age hardening curves of the alloys at 175, 200, and 225 °C that the alloys with various components almost showed the same trend of age hardening. While the higher the Sm content, the harder the alloy. With the Sm content increases, the yield strength (TYS) of cast alloys (F state) were obviously improved, however the tensile strength (UTS) became lower because of the quick drop of the elongation. The elongations of solid solution (T4) and aging (T6) alloy became lower, while the yield strength and tensile strength increased at first and then decreased. The optimized component is Mg-4Sm-0.4Zn-0.3Zr, which the mechanic properties at T6 state are: TYS=131MPa; UTS=261MPa; δ=6.8%.

Effect of Solution Treatment on Microstructure Evolution and Mechanical Behavior of Cu-20Ni-20Mn Alloy

2016 ◽  
Vol 850 ◽  
pp. 773-777
Author(s):  
Wei Bin Xie ◽  
Qiang Song Wang ◽  
Guo Liang Xie ◽  
Xu Jun Mi ◽  
Dong Mei Liu ◽  
...  
Keyword(s):  
Grain Size ◽  
Mechanical Behavior ◽  
Grain Growth ◽  
Microstructure Evolution ◽  
Hot Forging ◽  
Solution Treatment ◽  
Hardness Test ◽  
Solution Temperature ◽  
Second Phase ◽  
Solution Treated

The influence of solution treatment on microstructure evolution and mechanical behavior of Cu-20Ni-20Mn alloy was investigated by optical microscopy (OM), X-ray diffraction (XRD) and hardness test. The results revealed that both solution temperature and holding time had effect on the grain growth behavior. The grain growth activation energy was determined by grain size of Cu-20Ni-20Mn alloy for different heat treatment temperatures and periods. With increasing temperature of solution treatment, the second phase is gradually dissolved into the Cu-rich matrix, and the lattice parameter of the matrix solution treated at 1173K for 0.5 h was about 3.668 Å. The hardness of the solution-treated alloy was lower than that of hot forging, and the hardness value decreased with the increase of solution temperature, which may be attributed to grain size. The hardening ability, corresponding to the Hall-Petch relationship, decreased linearly with D-1/2.

Effect of Post Heat Treatment on the Microstructure and Tensile Properties of Nano TiC Particulate Reinforced Inconel 718 by Selective Laser Melting

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Solution Treatment ◽  
Nano Particles ◽  
Solution Temperature ◽  
Laser Melting ◽  
Post Heat Treatment ◽  
Particulate Reinforced

Abstract To strengthen the metal components by selective laser melting (SLM), adding reinforcement particles and applying post treatments are generally regarded as the two effective means. However, how post heat treatment affects the properties of nano particulate reinforced metal composites obtained by laser additive manufacturing (AM) processes has rarely been studied. In this study, Inconel 718 matrix composite reinforced by 0.5 wt% nano TiC particles was prepared using SLM. To evaluate the effect of the heat treatment routines on the performance of the SLM-produced composite, two levels of solution temperature (980 and 1100 °C) were designed, and the solution treatment was followed by a standard two-step aging (720 °C for 8 h and 620 °C for 8 h). Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) observations were performed to examine the microstructure, and transmission electron microscopy (TEM) observation was conducted to characterize the morphologies of incorporated nano particles and precipitated phases. Tensile tests were conducted to evaluate the mechanical properties of the formed composites. It was found that nano particles can effectively strengthen the metal matrix under both as-built and heat-treated conditions, and the material undergoes static recrystallization during the post heat treatment. Also, it was discovered that nano TiC particles play an important role in refining the microstructure of Inconel 718 composite below 980 °C. The maximum tensile strength of 1370 MPa was observed under 980 °C + aging condition, representing a 16% increase as compared with the unreinforced Inconel 718.

scholarly journals Microstructure Heredity of Inconel 718 Nickel-Based Superalloy during Preheating and Following Deformation

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 303
Author(s):  
Jianguo Wang ◽  
Dong Liu ◽  
Xiao Ding ◽  
Haiping Wang ◽  
Hai Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Dynamic Recrystallization ◽  
Inconel 718 ◽  
Volume Fraction ◽  
Effective Strain ◽  
Hot Working ◽  
Solution Temperature ◽  
Compression Tests ◽  
Δ Phase

Preheating and compression tests of Inconel 718 superalloy double cone specimens were carried out to investigate the microstructure heredity during hot working. Optical microscopy, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM) were used to characterize the microstructure evolution. The results show that intense microstructure heredity can be found at the temperature 960~990 °C. During the preheating process, δ phase precipitation or grain growth could increase the fraction of high angle grain boundary (HAGBs) and Σ3n boundaries. Otherwise, the generation or spread of annealing twin could increase the fraction of LAGBs, Volume fraction of recrystallized grains was evaluated at the whole hot working process. At the temperature of 960~990 °C, the volume fraction of recrystallized grains increases with effective strain increasing. At the super solution temperature of δ phase, the volume fraction of recrystallized grains decreases and then increases with the increase of the effective strain. The unimodal grain size distribution and fully recrystallized grains can be obtained at low strains at 960~990 °C. The twin boundary length fraction of deformed specimens is always lower than that of preheated ones. Discontinuous dynamic recrystallization (DDRX) was considered as the dominant nucleation mechanism, and continuous dynamic recrystallization (CDRX) was strengthened with the increasing grain size. Twin introduced deformation will be the main deformation mode for alloy 718 with larger grain.

Microstructure and Hall–Petch Behavior of Fe–Co-based Hiperco© Alloys

2000 ◽  
Vol 15 (4) ◽  
pp. 835-837 ◽  
Author(s):  
Chang-He Shang ◽  
R. C. Cammarata ◽  
T. P. Weihs ◽  
C. L. Chien
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Alloy Composition ◽  
Volume Fraction ◽  
Second Phase ◽  
Boundary Mobility ◽  
Grain Boundary Mobility ◽  
Nb Content ◽  
Cold Rolled ◽  
Scanning Electron

The microstructure and hardness of Fe–Co-based Hiperco© alloys were investigated. Scanning electron microscopy revealed elongated grains in the as-received (cast and cold-rolled) alloys, and samples containing Nb had second phase precipitates. Annealing of alloys for 1 to 3 h at temperatures in the range 700 to 800 °C resulted in grains becoming equiaxed. In the Nb-containing alloys, the original precipitates dissolved and new precipitates appeared. The rate of grain growth decreased with increasing Nb content, suggesting that Nb or Nb-containing precipitates were responsible for a reduction in the grain boundary mobility. The hardness as a function of grain size in the annealed samples of all of the alloys could be plotted on the same Hall–Petch curve, indicating that the yield strength of these alloys is governed by the grain size, independent of the alloy composition and volume fraction of precipitates.

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

Sign in / Sign up

Export Citation Format

Share Document