scholarly journals The Effect of Cyclic Solution Heat Treatment on the Martensitic Phase Transformation and Grain Refinement of Co-Cr-Mo Dental Alloy

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 861 ◽  
Author(s):  
Shahab Zangeneh ◽  
Hamid Reza Lashgari ◽  
Shaimaa Alsaadi ◽  
Sara Mohamad-Moradi ◽  
Morteza Saghafi
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Grain Refinement ◽  
Solution Heat Treatment ◽  
Thermal Stresses ◽  
Solution Treatment ◽  
Martensite Phase ◽  
Cyclic Heat Treatment ◽  
Uniform Dispersion ◽  
Ε Martensite

The present study was undertaken to investigate the effect of continuous and discontinuous (cyclic) solution heat treatment on the athermal and isothermal ε martensite phase transformation in Co-28Cr-6Mo-0.3C implant alloy. The results showed that the cyclic solution heat treatment induced more of the athermal ε martensite phase in the alloy than that of the continues one. In addition, the cyclic heat treatment contributes to the development of more isothermal martensite phase during isothermal aging at 850 °C and, moreover, grain refinement in the area beneath the sample surface. The severity of grain refinement was highly significant adjacent to the surface and decreased by increasing the distance from the sample free surface. This novel grain refinement in high-carbon Co-Cr-Mo alloy was attributed to the generation of larger quenching thermal stresses introduced beneath the surface during cyclic solution treatment. The repetitive heating/cooling cycle modifies the surface properties, refines the grain size and leads to uniform dispersion of the secondary carbides. The corrosion resistance of the cyclically solution heat-treated samples was superior as compared to the as-cast one.

The Martensitic Transformation in Ti-6Al-4V

2018 ◽  
Vol 914 ◽  
pp. 140-148 ◽  
Author(s):  
Zhi Chao Xu ◽  
H.P. Kriegel
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Nucleation Rate ◽  
Single Cells ◽  
Solution Treatment ◽  
Lattice Parameter ◽  
Rate Function ◽  
Martensite Phase ◽  
Solution Temperature ◽  
Scanning Calorimetry

The effect of heat treatment on the phase transformation of Ti-6Al-4V alloy was investigated. This heat treatment consisted of solution treatment at 850°C,900°C,950°Cfor 1h and subsequent water quenching. The phase transformation data was obtained by X-ray diffraction and differential scanning calorimetry (DSC).The differences were observed in the changes of lattice parameters of martensite phase among the different solution temperature. The volume of single cells for a' phase increases from 34.84 Å3 to 35.09 Å3 and then decreases to 34.63 Å3 with the solution temperature increased. These changes are believed to be due to partitioning of vanadium in b phase and its strong effect on the lattice parameter of a' martensite phase. The nucleation rate function has been obtained by thermodynamic theory. Based on these equations, it could be proved that the nucleation rate of martensite should be increased with the increase of the content of vanadium and the decrease of aluminum in b phase.

Formation of a Novel X Phase in Mg–Gd–Zn–Zr Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 623-626 ◽  
Author(s):  
Y.J. Wu ◽  
Li Ming Peng ◽  
X.Q. Zeng ◽  
D.L. Lin ◽  
W.J. Ding
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Phase Transformation ◽  
Grain Boundaries ◽  
Solution Heat Treatment ◽  
Long Period ◽  
Β Phase ◽  
Lpso Structure ◽  
Zr Alloy ◽  
Zr Alloys

The coherent fine-lamellae consisting of the 2H-Mg and the 14H-type long period stacking ordered (LPSO) structure within α'-Mg matrix have been observed in an as-cast Mg–Gd–Zn–Zr alloy. During subsequent solid solution heat treatment at 773 K, in addition to the lamellae within matrix, a novel lamellar X phase [Mg–(8.37±1.0)Zn–(11.32±1.0)Gd] with the 14H-type LPSO structure was transformed from the dendritical β phase. The 14H-type LPSO structure existing in Mg–Gd–Zn–Zr alloys derives from two variant ways: formation of the 14H-type LPSO structure comes from two variant means: i.e., the formation within matrix and the phase transformation from the β phase to the X phase in grain boundaries.

Study on Microstructures and Mechanical Properties of Die Casting Mg-xGd-3Y-0.5Zr Alloys

2013 ◽  
Vol 690-693 ◽  
pp. 44-48
Author(s):  
Feng Wang ◽  
Zhi Wang ◽  
Zheng Liu ◽  
Ping Li Mao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Solution Heat Treatment ◽  
Die Casting ◽  
Solution Treatment ◽  
Small Variation ◽  
Strength Increase ◽  
Microstructures And Mechanical Properties ◽  
Zr Alloys

In this paper, developed a non-aluminum die casting magnesium alloys were studied based on Mg-xGd-Y-Zr（x=6, 8, 12 wt.%）alloys in cold chamber press. The microstructures and mechanical properties of die casting GWK alloys have been investigated using OM, SEM, XRD, EDS and mechanical property test. The experimental results show that with increasing Gd content of Mg-xGd-Y-Zr alloys, the tensile strength increase, but elongation decrease. In particular, die casting GWK alloys after short-term and low-temperature solid solution treatment (T4) have a small variation in grain size and more uniform microstructures, and the second phases distribute at the grain boundaries in form of discontinuous rod shape or granule shape, which result in an obvious improvement in tensile mechanical properties of alloys. The Mg-12Gd-3Y-0.5Zr die casting alloy exhibit maximum tensile strength after solution heat treatment, and the value is 269MPa at room temperature. The effect of solution heat treatment on die casting Mg-xGd-Y-Zr alloys was also discussed.

Effect of the Two-Step Solution Heat Treatment on the Microstructure of Semisolid Cast 7075 Aluminum Alloy

2012 ◽  
Vol 488-489 ◽  
pp. 243-247 ◽  
Author(s):  
Saowalak Kongiang ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin ◽  
Sirikul Wisutmethangoon
Keyword(s):  
Heat Treatment ◽  
Treatment Condition ◽  
Solution Heat Treatment ◽  
Solution Treatment ◽  
Heat Treatment Condition ◽  
Single Step ◽  
Eutectic Phase ◽  
Solution Treated ◽  
The Matrix ◽  
Black Particle

Effect of the two-step solution heat treatment on the microstructure of semisolid cast 7075 aluminium alloy has been studied. The microstructure of the as-cast specimens mainly consisted of matrix-α (Al) and grain boundary (GB)-eutectic phase (α-Al + Mg(Zn,Cu,Al)2). After solution treating, coarse black particles were found to form in the single-step solution treated specimens at the condition of 450 °C for 8 h and 480 °C for 1 h, respectively. Two-step solution heat treatment resulted in the reduction of coarse black particle formation while maintaining the same amount of eutectic MgZn2phase dissolution as the high temperature single-step solution treatment. Therefore, the two-step solution heat treatment enables alloying elements dissolved into the matrix without overheating and hence decreases coarse black particles. The optimum two-step solution heat treatment condition derived from this study was 400 °C for 8 h + 450 °C for 4 h.

Microstructure & Phase Transformation in Rapidly Solidified V-Ga Alloys

1986 ◽  
Vol 80 ◽  
Author(s):  
M. W. Park ◽  
S. H. Whang ◽  
S. Karmarkar ◽  
D. Divecha
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Grain Refinement ◽  
Rapid Solidification ◽  
Rapid Quenching ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rapidly Solidified ◽  
A15 Phase

AbstractThe A15 Phase forming V-Ga alloys were processed into ribbons and foils by rapid solidification techniques. Microstructures and phase transformation in these alloys by rapid solidification and succeeding heat treatment were investigated by x-ray diffraction and TEM. It is shown that equilibrium A15 phases can readily be suppressed by rapid quenching in these alloys. A significant grain refinement resulting from the rapid solidification also was observed. Microhardnesses of these alloys as a function of Ga concentration were determined.

Optimisation of the Solution Heat Treatment of Rheo-Processed Al-Cu-Mg-(Ag) Alloys A206 and A201

2009 ◽  
Vol 618-619 ◽  
pp. 353-356 ◽  
Author(s):  
E.P. Masuku ◽  
Heinrich Möller ◽  
R.D. Knutsen ◽  
L. Ivanchev ◽  
Gonasagren Govender
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Solution Treatment ◽  
Dsc Analysis ◽  
Optimum Solution ◽  
Hardness Values

The traditional solution treatment cycles that are currently applied to rheo-processed A201 are mostly those that are used for conventional castings. These solution treatments are not necessarily the optimum solution treatments for rheo-processing. As a result, DSC analysis was done to optimize this heat treatment. The new solution treatment, which consists of higher temperatures and shorter times (515°C/5h, followed by 570°C/10h), resulted in slightly higher hardness values for both alloy A206 and A201.

Solution Heat Treatment of 7075 Aluminum Alloy Affected on Anodic Oxide Layer

2016 ◽  
Vol 867 ◽  
pp. 19-23 ◽  
Author(s):  
Itsaree Iewkitthayakorn ◽  
Somjai Janudom ◽  
Narissara Mahathaninwong
Keyword(s):  
Heat Treatment ◽  
Oxide Film ◽  
Solution Heat Treatment ◽  
Treatment Time ◽  
Solution Treatment ◽  
Secondary Phase ◽  
Anodic Oxide ◽  
Al Alloy ◽  
Heat Treated

This research focused on the effect of solution heat treated microstructures on anodic oxide formations of casting 7075 Al alloy. The casting specimens were solution heat treated at 450°C for various holding. The results showed that the quality of anodic oxide film on the specimen with 4h solution heat treatment time was higher than that of at other conditions. Because its microstructures obtained the lowest amounts of secondary phase particles leading to improve the quality of oxide film and also reduce defects in oxide film. On the other hand, coarse black particles of Mg2Si formed increasingly in microstructures of specimens after solution treatment at prolong holding time of 8h and 16h resulted in discontinues oxide films forming on them.

scholarly journals Selection of optimal solution heat treatment of the casting cylinder heads

2018 ◽  
Vol 157 ◽  
pp. 02053 ◽  
Author(s):  
Eva Tillová ◽  
Mária Chalupová ◽  
Lenka Kuchariková ◽  
Juraj Belan ◽  
Denisa Závodská
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Treatment Time ◽  
Crack Nucleation ◽  
Particle Density ◽  
Solution Treatment ◽  
Optimal Solution ◽  
Solution Temperature ◽  
Selection Of

The effect of solution treatment on mechanical properties (UTS, elongation, Brinell hardness) and microstructure (Si-morphology and Si-size) of an aluminium alloy (A356) used for casting cylinder heads was studied. The tests were carried out with specimens machined from the bulkheads of V8 engine blocks cast by the low pressure process. The samples were tested in as-cast and T6 heat treating conditions (solution heat treatment at 530°C with different time - 2, 3, 4, 5, 6, 7 hours, quenching in water at 20°C and precipitation hardened for 4 hour at 160°C). The results show that used heat treatment improves mechanical properties of the cylinder head casts. Tensile strength and hardness of specimens increase with solution treatment time. The hardness is a reflection of solution strengthening and silicon particle distribution in matrix. Solution temperature 530°C and 5 hours solution time is appropriate to obtain better morphology and distribution of Si particles in microstructure. Prolonged solution treatment (more than 5 hours) leads to a coarsening of the Si particles, while the numerical Si density decreases. As the particle density decreases, a fewer number of sites are available for crack nucleation, and hence, the fracture properties are improved. The data obtained from this study will be used to improve process control, and to help the selection of heat treatment of the casting for future products.

Effect of Ageing Treatment on the Microstructures of Ti-50.7at.%Ni Shape Memory Alloy

2013 ◽  
Vol 686 ◽  
pp. 180-191
Author(s):  
Kurnia Hastuti ◽  
Esah Hamzah ◽  
Jasmi Hashim
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Ageing Time ◽  
Solution Treatment ◽  
Hardness Test ◽  
Optical Microscope ◽  
Atomic Diffusion ◽  
Ageing Treatment ◽  
The Matrix ◽  
One Step

In this study, a commercial Ti-50.7at.%Ni was subjected to solution treatment at 800oC and 900oC for one hour followed by ageing at 300oC, 400oC, 500oC and 600oC for 1 hour, 2 hours and 4 hours respectively. Characterization of the material using optical microscope, XRD, FESEM and EDX has shown that the presence of Ti2Ni and Ti-rich precipitates in the as-received material remained unchanged even after heat treatment. The presence of oxygen in the air condition heat treatment has stabilized Ti2Ni since this condition causing the formation of Ti4Ni2O which is also determined as Ti2Ni due to their same crystal structure. The formation of Ti3Ni4 precipitates during ageing encouraged the establishment of R phase instead of martensite due to the depletion of Ni content in the matrix. Ageing treatment at 300oC generates two steps of R phase transformation due to the differences in Ni composition in the matrix at the grain boundary and grain interior region. However, for samples subjected to ageing at higher temperature, 400-500oC, only one step of R phase transformation occurred because Ni atomic diffusion was not forbidden in the high temperature. Hardness test performed on the samples revealed that increasing the ageing time will increase the hardness of material; however for the sample aged at 600oC, increasing the ageing time would reduce the hardness due to dissolution of Ti3Ni4 precipitaes into the matrix.

The Effect of Solution Time on the Microstructure of A356.2 Aluminum Alloy Provided by Rheocasting and Squeeze Casting

2022 ◽  
Vol 327 ◽  
pp. 189-196
Author(s):  
Le Cheng ◽  
Hong Xing Lu ◽  
Min Luo ◽  
Xing Gang Li ◽  
Wan Peng Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Production Efficiency ◽  
Treatment Process ◽  
Squeeze Casting ◽  
Solution Process ◽  
Solution Treatment ◽  
Solution Time ◽  
Conventional Solution ◽  
Short Time

The evolution of the microstructure of A356.2 alloys prepared by the rheocasting and squeeze casting during solution heat treatment was investigated. In contrast with the conventional solution heat treatment process (3 hours at 540oC), a short time solution treatment process (less than 1 hour at 540oC) is applied in this paper. The results show that the rheocastings require a shorter solution time than the squeeze-castings to obtain spheroidized Si particles. After solution for 10 min, the X-ray diffraction inspection results show that the Mg2Si phase completely is dissolved in both rheocastings and squeeze-castings. However, a small amount of Mg2Si is found at the edge of the Si particle by scanning electron microscope observation. After solution for more than 20 min, the Mg2Si phase is completely dissolved. Fe-rich phases, including AlSiFeMg and AlFeSi, exist throughout the solution process. The developed T6 heat treatment with a short solution time can effectively improve production efficiency and decrease process cost for the rheocasting process. Key words: A356.2 alloy, microstructure, short solution time, rheocasting, squeeze casting

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