The Effect of Heat Treatment on the Microstructure of Ti-45Al-5Nb-0.3Y Alloy

2009 ◽  
Vol 614 ◽  
pp. 55-59
Author(s):  
Fan Tao Kong ◽  
Yu Yong Chen
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Lamellar Microstructure ◽  
Air Cooling ◽  
Water Cooling ◽  
Different Temperatures ◽  
Combined Action ◽  
Average Size ◽  
Equiaxed Grains ◽  
Fully Lamellar

Effects of heat treatment on the microstructure of as-cast and as-forged Ti-45Al-5Nb-0.3Y alloy are discussed. The as-cast Ti-45Al-5Nb-0.3Y alloy exhibits a microstructure consisting of fine equiaxed grains which average size is almost 100μm. Phase transformation of as-cast Ti-45Al-5Nb-0.3Y alloy greatly depends upon cooling rate. During furnace cooling, the alloy transform to fully lamellar microstructure. During air cooling, massive transformation predominates. During oil cooling, extremely fine fully lamellar microstructure is formed. During water cooling, ordering α2 phases are primary. Thermo-mechanical treatments, through combined action of hot canned forging and heat treatment, were performed on a Ti-45Al-5Nb-0.3Y alloy to investigate their effect on the microstructure of the alloy. The as-forged Ti-45Al-5Nb-0.3Y alloy is comprised of a large number of dynamic recrystallization (DRX) γ grains, curved and broken lamellae, and a small amount of remnant lamellae. And three different microstructures, duplex (DP), nearly lamellar (NL) and fine fully lamellar (FFL), have been obtained through heat treatment at different temperatures (1320-1370°C), respectively.

Residual Stress Analysis Considering Phase Transformation and Transformation Plasticity for Heat-Treated Large Size Shaft

2016 ◽  
Vol 725 ◽  
pp. 647-652 ◽  
Author(s):  
Yusuke Yanagisawa ◽  
Yasuhiro Kishi ◽  
Katsuhiko Sasaki
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Phase Transformation ◽  
Air Cooling ◽  
Water Cooling ◽  
Stress Distributions ◽  
Transformation Plasticity ◽  
Large Size ◽  
Heat Treated ◽  
Good Agreement

The residual stress distributions of the forgings after both water-cooling and air-cooling were measured experimentally. The residual stress occurring during the heat-treatment was also simulated considering the phase transformation and the transformation plasticity. A comparison of the experiments with the simulations showed a good agreement. These results shows that the transformation plastic strain plays an important role in the heat treatment of large forged shafts.

Effect of Secondary Cooling on Non-Oriented Electrical Steel Strips Produced by Twin-Roll Casting Process

2013 ◽  
Vol 690-693 ◽  
pp. 218-221
Author(s):  
Ting Zhang ◽  
Xiao Ming Zhang ◽  
Zhi Yuan Guo ◽  
Yu Qian Wang ◽  
Cheng Gang Li
Keyword(s):  
Electrical Steel ◽  
Casting Process ◽  
Air Cooling ◽  
Secondary Cooling ◽  
Twin Roll Casting ◽  
Steel Strips ◽  
Roll Casting ◽  
Average Size ◽  
Equiaxed Grains ◽  
Twin Roll

Effect of secondary cooling on non-oriented electrical steel strips was investigated. The 2.0 mm thick cast strips contain two compositions were produced by twin-roll casting process, cooled in the air or cooled by spraying water. The microstructure was observed by optical microscopy, and EBSD was used to characterize the texture of the cast strips. The results showed that air-cooling cast strips have uniform and equiaxed grains with average size of 250 μm. The microstructure of the water-spraying cast strips compose of most equiaxed grains and a small number of abnormal big grains. At the same time, the secondary cooling rate mildly affects the cast texture strength but has no influence on the texture type.

scholarly journals Effects of deformation on the microstructure of a Ti-V microalloyed steel in the phase transition region

2004 ◽  
Vol 57 (4) ◽  
pp. 303-311
Author(s):  
Wiliam Regone ◽  
Sérgio Tonini Button
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
Transition Region ◽  
Microstructural Evolution ◽  
Microalloyed Steel ◽  
Hot Forging ◽  
Microalloyed Steels ◽  
Air Cooling ◽  
Water Cooling ◽  
Phase Transition Region

Microalloyed steels are used in the forging of many automotive parts like crankshafts and connecting rods. They are hot worked in a sequence of stages that includes the heating to the soaking temperature, followed by forging steps, and finally the controlled cooling to define the microstructure and mechanical properties. In this work it was investigated the thermomechanical behavior and the microstructural evolution of a Ti-V microalloyed steel in the phase transition region. Torsion tests were done with multiple steps with true strain equal to 0.26 in each step. After each torsion step the samples were continuous cooled for 15 seconds to simulate hot forging conditions. These tests provided results for the temperature at the beginning of the phase transformation, and allowed to analyze the microstructural changes. Also, workability tests were held to analyze the microstructural evolution by optical and scanning electron microscopy. Results from the torsion tests showed that the temperature for the beginning of phase transformation is about 700 ºC. Workability tests held at 700 ºC followed by water-cooling presented microstructures with different regions: strain hardened, and static and dynamic recrystallized. Workability tests at 700 ºC followed by air-cooling showed a complex microstructure with ferrite, bainite and martensite, while tests at 650 and 600 ºC followed by water-cooling showed a microstructure with allotriomorphic ferrite present in the grain boundaries of the previous austenite.

scholarly journals Study on the Effect of High-Temperature Heat Treatment on the Microscopic Pore Structure and Mechanical Properties of Tight Sandstone

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Liangbin Dou ◽  
Guanli Shu ◽  
Hui Gao ◽  
Jinqing Bao ◽  
Rui Wang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Pore Structure ◽  
Water Cooling ◽  
Tight Sandstone ◽  
The Core ◽  
Core Samples ◽  
High Temperature Heat Treatment ◽  
Different Temperatures ◽  
Cooling Methods

The investigation of changes in physical properties, mechanical properties, and microscopic pore structure characteristics of tight sandstone after high-temperature heat treatment provides a theoretical basis for plugging removal and stimulation techniques, such as high energy gas fracturing and explosive fracturing. In this study, core samples, taken from tight sandstone reservoirs of the Yanchang Formation in the Ordos Basin, were first heated to different temperatures (25-800°C) and then cooled separately by two distinct cooling methods—synthetic formation water cooling and natural cooling. The variations of wave velocity, permeability, tensile strength, uniaxial compressive strength, and microscopic pore structure of the core samples were analyzed. Experimental results demonstrate that, with the rise of heat treatment temperature, the wave velocity and tensile strength of tight sandstone decrease nonlinearly, yet its permeability increases nonlinearly. The tight sandstone’s peak strength and elastic modulus exhibit a trend of the first climbing and then declining sharply with increasing temperature. After being treated by heat at different temperatures, the number of small pores varies little, but the number of large pores increases obviously. Compared to natural cooling, the values of physical and mechanical properties of core samples treated by synthetic formation water cooling are apparently smaller, whereas the size and number of pores are greater. It can be explained that water cooling brings about a dramatic reduction of tight sandstone’s surface temperature, generating additional thermal stress and intensifying internal damage to the core. For different cooling methods, the higher the core temperature before cooling, the greater the thermal stress and the degree of damage caused during the cooling process. By taking into consideration of changes in physical properties, mechanical properties, and microscopic pore structure characteristics, the threshold temperature of tight sandstone is estimated in the range of 400-600°C.

New Results of the Heat-Treated CuZn39Pb3 Brass Behavior and Resistance to Cavitation Erosion

2021 ◽  
Vol 890 ◽  
pp. 173-180
Author(s):  
Ilare Bordeaşu ◽  
Nicușor Alin Sîrbu ◽  
Iosif Lazăr ◽  
Ion Mitelea ◽  
Cristian Ghera ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Cavitation Erosion ◽  
Stress Relief ◽  
Air Cooling ◽  
Water Cooling ◽  
Characteristic Parameters ◽  
Volume Heat ◽  
Heat Treated ◽  
Hardness Increase

The paper presents the results of the behavior and resistance to the erosion by vibrating cavitation of the CuZn39Pb3 brass, obtained by quenching the volume heat treatment from 800°C with water cooling, followed by the stress-relief to 250°C, with air cooling. Comparison with both the delivery status and the naval brass (used for ship propellers), based on the characteristic parameters values, recommended by the ASTM G32 standards and used in the Cavitation Laboratory of the Polytechnic University of Timisoara, shows that the hardness increase resulted from the heat treatment led to a significant increase of resistance to vibrating cavitation.

Microstructures and Creep Properties of Powder Metallurgy Ti-48Al-2Cr-2Nb + W

2007 ◽  
Author(s):  
H. Saari ◽  
S. Bulmer ◽  
D. Y. Seo ◽  
P. Au
Keyword(s):  
Heat Treatment ◽  
Powder Metallurgy ◽  
Lamellar Microstructure ◽  
Controlled Cooling ◽  
Tial Alloys ◽  
Creep Properties ◽  
Rupture Ductility ◽  
Heat Treated ◽  
Fully Lamellar ◽  
Lamellar Interfaces

The microstructures and creep properties at 760 °C and 276 MPa of three powder metallurgy TiAl alloys (Ti-48Al-2Cr-2Nb, Ti-48Al-2Cr-2Nb+0.5W, and Ti-48Al-2Cr-2Nb+1W (atomic percent)) are presented. The results indicate that the addition of W to the base composition, the use of a solution heat treatment combined with controlled cooling (to generate a fully lamellar microstructure), and the use of an aging heat treatment (to generate precipitate particles at the lamellar interfaces) improve creep properties dramatically. The solution heat treated and aged Ti-48Al-2Cr-2Nb+1W alloy has a time to 0.5% strain of 8.3 hours, a time to 1% strain of 46.4 hours, and a creep life of 412 hours with a rupture ductility of 16.9%.

Effect of Heat Treatment on the Properties of Inconel X-750

2005 ◽  
Vol 297-300 ◽  
pp. 1220-1222
Author(s):  
Shi Chang Cheng ◽  
Zhao Jie Lin ◽  
Gang Yang ◽  
Zheng Dong Liu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Impact Toughness ◽  
Room Temperature ◽  
Solution Treatment ◽  
Heat Treatments ◽  
Air Cooling ◽  
Solid Solution Treatment ◽  
Different Temperatures

The authors experimentally investigated the change of mechanical properties of Inconel X-750 alloy under various heat treatments. For the selected specimens, solid solution treatment under different temperatures was carried out, followed air cooling or furnace cooling. Results show that suitable solid solution treatment and air cooling enhances the strength, plasticity, impact toughness at room temperature of the alloy and lowers the hardness of the alloy at room temperature.

Role of Equiaxed Primary Alpha (α׳) and Mechanical Properties of Ti-6Al-4V Alloy

2012 ◽  
Vol 510-511 ◽  
pp. 420-428
Author(s):  
A. Ahmad ◽  
A. Ali ◽  
G.H. Awan ◽  
K.M. Ghauri ◽  
R. Aslam
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Volume Fraction ◽  
Lamellar Microstructure ◽  
Phase Region ◽  
Bimodal Microstructure ◽  
Two Phase ◽  
Primary Alpha ◽  
Fully Lamellar

The paper presents the role of equiaxed α׳ in the bimodal microstructure to attain an optimal combination of ductility and strength. The study revealed that the production of bimodal microstructure and volume fraction of equiaxed α׳ were reliant on the forging temperature and subsequent heat treatment. The Ti-6Al-4V alloy was forged in the two phase region and different heat treatment cycles were employed to get the desired bimodal microstructure and thus the combination of strength and ductility. The mechanical properties of fully lamellar microstructure were compared with bimodal microstructure containing equiaxed α׳. The experimental results showed that the amount of equiaxed α׳ in the bimodal microstructure was critical for achieving a well-balanced profile of mechanical properties.

Effects of Different Heat Treatment Temperatures on the Properties of Quartz Fibers

2010 ◽  
Vol 105-106 ◽  
pp. 115-118 ◽  
Author(s):  
Qi Hong Wei ◽  
Chong Hai Wang ◽  
Zhi Qiang Cheng ◽  
Ling Li ◽  
Hong Sheng Wang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Phase Transformation ◽  
Fiber Strength ◽  
Single Fiber ◽  
Significant Phase ◽  
Surface Micromorphology ◽  
Heat Treated ◽  
Different Temperatures ◽  
Crystallization Heat

In this paper, XRD was engaged in studying phase transformation of quartz fibers, SEM was engaged in studying the surface micromorphology of quartz fibers heat treated at different temperatures, and the tensile strength was measured by a single fiber strength electronics instrument. The results indicate that surface infiltration agent have been iliminated after heat treatment at 500°C, and the tensile strength decreaced significantly. The higher the temperature was, the more the tensile strength decreaced. There were no significant phase transformation and no crystallization heat treatmented at 500~800°C. But there were some round and strip bulges, and scap defects on the surface. With temperature increasing,some scab defects and bulges began to flake off, and some new rifts and cracks were formed. This was one of the important factors that decreaced tensile strength markedly.

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