Article
Materials Science, Multidisciplinary
Morteza Taheri, Mansour Razavi, Seyed Farshid Kashani-Bozorg, Mohammad Javad Torkamany
Summary: Investigating the solidification and liquation cracks in Nd:YAG pulsed-laser welded GTD-111 nickel-base superalloy joints revealed a strong correlation between liquation cracks in the partially melted zone of base metal and solidification cracks in the weld metal. The study also found that increasing the pulse frequency can reduce the tendency to form both types of cracks.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Materials Science, Multidisciplinary
Morteza Taheri, Seyed Farshid Kashani-Bozorg, Ali Alizadeh, Mohsen Heydari Beni, Jafar Eskandari Jam, Ali Khorram
Summary: The weldability of GTD-111 superalloy by electron beam welding was studied, with a focus on the cracking evolution of solidification and liquation, and microstructural characteristics. By increasing heat input, both solidification and liquation cracks can be reduced, attributed to the decrease in cooling stress and increase in backfilling capacity.
MATERIALS RESEARCH EXPRESS
(2021)
Article
Materials Science, Multidisciplinary
Morteza Taheri, Seyed Farshid Kashani-Bozorg, Vaira Vignesh Ramalingam, Behzad Babaei, Ayyub Halvaee
Summary: This study investigated the melting rate of GTD-111 Nickel-based superalloy sheet in Nd:YAG pulsed-laser welding by exploring the effects of various parameters. Keyhole formation was found to play a crucial role in the sudden increase in melting rate, with pulse energy being the most effective parameter for keyhole formation. A suitable range for maximizing the melting rate in the keyhole mode was introduced after separately investigating the effects of welding speed and pulse frequency.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2021)
Article
Engineering, Mechanical
Morteza Taheri, Ayyub Halvaee, Seyed Farshid Kashani Bozorg, Ali Salemi Golezani, Rohallah Panahi Liavoli, Ali Akbar Kashi
Summary: This study evaluated the creep characteristics of GTD-111 superalloy and its weldment, finding that weld metal has the longest creep life, while the HAZ of heat-treated specimens showed a 17-hour longer creep life compared to cast specimens. Reduction of harmful phases can decrease defect occurrence and extend creep life in HAZ.
ENGINEERING FAILURE ANALYSIS
(2021)
Article
Materials Science, Multidisciplinary
Feng Wang, Morteza Taheri
Summary: This research investigated the effects of heat treatment, pre-heating, and pre-cold temperatures on hot cracks and microstructure of GTD-111 superalloy laser weld joints. The study found that different temperature conditions led to changes in the welding regions and factors such as heating rate, cooling rate, and segregation of alloying elements were identified as key influences.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Materials Science, Coatings & Films
Yan Cao, Naeim Farouk, Morteza Taheri, Alexei Valerievich Yumashev, Seyed Farshid Kashani Bozorg, Olatunji Oladimeji Ojo
Summary: The study found that increasing the laser power led to the formation of equiaxed grains and an increased tendency for liquated cracks at 300 W due to the expansion of the heat-affected zone. Furthermore, an increase in the powder feeding rate resulted in a decrease in dendritic arm spacing at the coating bottom.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Morteza Taheri, Amirreza Kazemi, P. Gurusamy, Arash Rasoulpouraghdam, V Mohanavel, M. Ravichandran, Moslem Paidar
Summary: The study found that the hybrid laser-arc welding method provides more heat input compared to laser beam welding, which helps expel pores and provides conditions for nonhomogeneous nucleation.
Article
Materials Science, Multidisciplinary
Zhongbin Wei, Morteza Taheri, Chunfeng Li, Sadok Mehrez
Summary: The present study introduces a new joining technique called laser pressure welding for welding the GTD111 superalloy used in gas turbine blades. LPW causes complex microstructural changes in the weld metal, base metal, and heat-affected zone by absorbing more laser energy in the weld seam. Simultaneously applying rolling pressure and heat input has a significant effect on reducing the porosity of the weld metal.
Article
Materials Science, Multidisciplinary
Morteza Taheri, Ayyub Halvaee, Seyed Farshid Kashani-Bozorg
Summary: This paper investigated the liquation cracking and strain-age cracking behavior of nickel-based GTD-111 superalloy welded by Nd:YAG pulse laser through various heat treatment cycles. The study aimed to develop a suitable microstructure for a defect-free weld. Parameters such as gamma', gamma-gamma' eutectic, MC carbide, Boride, and Ni-Zr intermetallic phase were identified as crucial in the formation of grain boundary melt and cracks in casting conditions.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Morteza Taheri, Ali Davar, Mohsen Heydari Beni, Jafar Eskandari Jam, Mohammad Reza Zamani, Ali Alizadeh
Summary: This study investigated the impact behavior of GTD-111 superalloy in different temperature conditions and found that the highest impact toughness was achieved at 600 degrees Celsius. Observations showed that cracks mainly originated from MC carbides, resulting in decreased toughness at low temperatures. Ductile failure was observed at 600 degrees Celsius, while the increase in alloy strength due to strain hardness and dislocation accumulation led to a decrease in impact toughness at 750 degrees Celsius and above.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2023)
Article
Optics
Mahmoud Afshari, Fatemeh Taher, Mohammad Reza Samadi, Mohsen Ayaz
Summary: This research optimized the mechanical properties of the weld joint between GTD-111 superalloy and 4340 steel through Nd:YAG pulsed laser welding process. The results showed that adjusting laser power and welding speed had significant impacts on the tensile strength, hardness, elongation, and weld penetration.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Sindo Kou
Summary: The study demonstrates that CALPHAD-based modeling can help predict the susceptibility of alloys to liquation and solidification cracking. By comparing the relationship between temperature and solid fraction in the weld metal, the susceptibility to cracking can be assessed. The composition of the weld metal, influenced by the workpiece, filler metal, and dilution, plays a key role in predicting susceptibility to cracking.
Article
Engineering, Manufacturing
Hong Li, Weijia Yan, Zhuoxin Li, Bober Mariusz, Jacek Senkara, Yu Zhang
Summary: A CALPHAD-coupled finite element model was established to investigate the formation mechanism of hot cracks in dissimilar resistance spot welding joints. The results showed that the composition of the local area played a key role in crack initiation. Two types of liquation cracks, Type I and Type II, were observed at the interface of the nugget and the base materials. Metallographic and energy dispersive spectrometer analysis revealed that the Type I cracks were filled by liquid within the nugget, while the Type II cracks and solidification cracks created no-bonding areas. The Type II cracks deteriorated the mechanical properties of the joints.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Materials Science, Multidisciplinary
K. S. Athira, P. Pandey, K. V. Phani Prabhakar, K. Chattopadhyay, S. Chatterjee
Summary: A new class of W-free, precipitation strengthened Co-base superalloys has been developed, which has improved high-temperature strength and excellent oxidation and hot corrosion resistance. This study investigates the impact of fusion welding on the microstructure and properties of a specific alloy in this class and finds that the welding-induced microstructural changes can be restored by a post-weld solutionizing-aging treatment.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Metallurgy & Metallurgical Engineering
Javad Asadi, Seyed Abdolkarim Sajjadi, Hamid Omidvar
Summary: Increasing joining time can reduce and eventually eliminate intermetallic phases, completing isothermal solidification. With increased holding time at all bonding temperatures, the thickness of the athermally solidified zone and the volume fraction of precipitates in the bonding area decrease, while the width of the diffusion affected zone increases.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2021)
Article
Engineering, Manufacturing
Guiju Zhang, Caiyuan Xiao, Morteza Taheri
JOURNAL OF MANUFACTURING PROCESSES
(2020)
Article
Materials Science, Multidisciplinary
Feng Wang, Morteza Taheri
Summary: This research investigated the effects of heat treatment, pre-heating, and pre-cold temperatures on hot cracks and microstructure of GTD-111 superalloy laser weld joints. The study found that different temperature conditions led to changes in the welding regions and factors such as heating rate, cooling rate, and segregation of alloying elements were identified as key influences.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Yan Cao, Abdeliazim Mustafa Mohamed, Samira Moshtaghi, Morteza Taheri, Mohammad Javad Torkamany
Summary: This study investigated the creep behavior of Ni3Al-base superalloy through small punch creep test, revealing that the difference in creep life in different specimens is related to the heat-affected zone and weld metal, with factors including coarsening, liquation, and grain boundary cracking playing a significant role in reducing creep life. Moreover, the elimination of Cr-Mo and Ni-Zr phases in heat-treatment specimens was observed due to their dissolution.
Article
Materials Science, Multidisciplinary
Morteza Taheri, Arash Rasoulpouraghdam, Azadeh Lohrasbi-Nejad, Seyed Farshid Kashani-Bozorg, Rohallah Panahi Liavoli
Summary: The microstructure and creep behavior of IN625 coatings on Rene80 alloy were studied, revealing that specific heat treatment conditions can significantly extend the creep life. Liquation cracks in the heat affected zone of cast-coated specimens were found to be the main reason for reduced creep life, with failure occurring at the coating-substrate interface.
MATERIALS RESEARCH EXPRESS
(2021)
Article
Materials Science, Multidisciplinary
Morteza Taheri, Seyed Farshid Kashani-Bozorg, Ali Alizadeh, Mohsen Heydari Beni, Jafar Eskandari Jam, Ali Khorram
Summary: The weldability of GTD-111 superalloy by electron beam welding was studied, with a focus on the cracking evolution of solidification and liquation, and microstructural characteristics. By increasing heat input, both solidification and liquation cracks can be reduced, attributed to the decrease in cooling stress and increase in backfilling capacity.
MATERIALS RESEARCH EXPRESS
(2021)
Article
Materials Science, Multidisciplinary
Morteza Taheri, Amirreza Kazemi, P. Gurusamy, Arash Rasoulpouraghdam, V Mohanavel, M. Ravichandran, Moslem Paidar
Summary: The study found that the hybrid laser-arc welding method provides more heat input compared to laser beam welding, which helps expel pores and provides conditions for nonhomogeneous nucleation.
Article
Materials Science, Multidisciplinary
Morteza Taheri, Mansour Razavi, Seyed Farshid Kashani-Bozorg, Mohammad Javad Torkamany
Summary: Investigating the solidification and liquation cracks in Nd:YAG pulsed-laser welded GTD-111 nickel-base superalloy joints revealed a strong correlation between liquation cracks in the partially melted zone of base metal and solidification cracks in the weld metal. The study also found that increasing the pulse frequency can reduce the tendency to form both types of cracks.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Optics
Ali Khorram, Morteza Taheri
Summary: The study found that increasing heat input through laser reduces the sensitivity to cracks in the ceramic coating and rejuvenated zone. The solidification rate and temperature gradient were identified as the most important factors controlling the microstructure in the rejuvenated zone. The uniform and homogeneous coating of Metco 204NS greatly enhances the wear resistance of the alloy.
Article
Materials Science, Multidisciplinary
Zhaoyang Zuo, Morteza Taheri, Mansour Razavi, Mohammad Javad Torkamany, Arash Rasoulpouraghdam, R. Vaira Vignesh
Summary: The study found that increasing the magnetic induction field can refine the grains and enhance the hardness of the laser-cladded layer, thus improving its wear resistance.
Article
Materials Science, Multidisciplinary
Song Zhao, Morteza Taheri, Kourosh Shirvani, Mehdi Naserlouei, Khashayar Beirami, Moslem Paidar, Wei Sai
Summary: Refractory high-entropy alloys (RHEAs) based on NbMoTaTiNi were prepared using laser cladding with the use of an ultrasonic field. The microstructural characteristics, grain size, residual stress, wear, and hardness of the coating were evaluated. The results showed that the coating had a biphasic structure, consisting of γ (Ni) and NbMoTaTiNi phases. The use of the ultrasonic field resulted in a uniform distribution of the NbMoTaTiNi phase throughout the coating, while without the ultrasonic field, un-melted large particles of NbMoTaTiNi powder were observed. This caused an increase in the residual tension of the coating. The use of the ultrasonic field also led to the transformation of columnar grains to equiaxed grains and a reduction in structural defects. The formation of equiaxed grains with zigzag grain boundaries reduced the friction coefficient, wear volume loss, and wear rate of the coating.
Article
Materials Science, Multidisciplinary
Morteza Taheri, Mansour Razavi
Summary: This study investigates the effect of the ultrasonic field on the preparation of amorphous/crystalline Fe-based coatings. Fe86.3Si5.9B3.2Cr4.6 (wt%) powder was deposited on GTD-111 superalloy substrate with and without ultrasonic field. The use of an ultrasonic field inhibits columnar growth and creates equiaxed grains, while also increasing the amorphous phase by 34.5%. The results show improved corrosion behavior and reduced friction coefficient when using the ultrasonic field.
MATERIALS RESEARCH EXPRESS
(2023)
Article
Engineering, Multidisciplinary
Morteza Taheri, Seyed Farshid Kashani-Bozorg, Hamid Reza Teymouri, Amir Hossein Fallah-Morad, Rohallah Panahi Liavoli, Amirreza Davar
Summary: The study investigated the impact behavior of IN738 superalloy welded by pulsed laser under different heat treatment conditions and temperatures. Results showed that the lowest fracture toughness was related to specimens welded under casting conditions. As temperature increased, impact toughness initially increased due to free dislocations causing ductile behavior, but decreased above 770 degrees C as a result of decreased strength from dislocation passage through obstacles.
ENGINEERING RESEARCH EXPRESS
(2021)
Article
Engineering, Multidisciplinary
Morteza Taheri, Ayyub Halvaee, Ali Salemi Golezani, Ali Akbar Kashi
ENGINEERING RESEARCH EXPRESS
(2020)