Showing 3 results for Palizdar
H. Torkamani, H. Rashvand, Sh. Raygan, J. Rassizadehghani, Y. Palizdar, C. Garcia Mateo, D. San Martin,
Volume 14, Issue 3 (September 2017)
Abstract
In industry, the cost of production is an important factor and it is preferred to use conventional and low cost procedures for producing the parts. Heat treatment cycles and alloying additions are the key factors affecting the microstructure and mechanical properties of the cast steels. In this study an attempt was made to evaluate the influence of minor Mo addition on the microstructure and mechanical properties of conventionally heat treated cast micro-alloyed steels. The results of Jominy and dilatometry tests and also microstructural examinations revealed that Mo could effectively increase the hardenability of the investigated steel and change the microstructure features of the air-cooled samples. Acicular microstructure was the consequence of increasing the hardenability in Mo-added steel. Besides, it was found that Mo could greatly affect the isothermal bainitic transformation and higher fraction of martensite after cooling (from isothermal temperature) was due to the Mo addition. The results of impact test indicated that the microstructure obtained in air-cooled Mo-added steel led to better impact toughness (28J) in comparison with the base steel (23J). Moreover, Mo-added steel possessed higher hardness (291HV), yield (524MPa) and tensile (1108MPa) strengths compared to the base one.
S. Gholami Shiri, Y. Palizdar, . A. Jenabali Jahromi, Eduardo F. de Monlevade,
Volume 15, Issue 3 (September 2018)
Abstract
The relation between microstructure and the fracture mechanisms of δ-TRIP steel with different Nb-content has been investigated using complementary methods of light microscopy, SEM, EDS, EBSD, X-ray phase analysis and tensile test. The results revealed a close dependency between the presences of constitutive phases i.e. ferrite, bainite, retained austenite and martensite and the mode and characteristics of fracture. All samples revealed almost different fractography pattern which could be associated to the effect of Nb microalloying element. The different fractography patterns were consisted of dimple rupture, riverside and Wallner lines pattern. The proportion of the cleavage fracture in comparison of dimple rapture increased by increasing the Nb-content due to the increase of primary martensite in the microstructure.
M. Palizdar, Z. Aslam, R. Aghababazadeh, A. Mirhabibi, P. Sangpour, Z. Abadi, Y. Palizdar, R. Brydson,
Volume 16, Issue 4 (December 2019)
Abstract
In this paper the chemical interaction between catalyst and support has been studied to understand the observed different growth rate of CNTs in our previous paper. Both pure MgO and Mg(NO3)2 . 6H2O as sources of the MgO catalyst support and Fe2(SO4)3 · xH2O as the source of the Fe catalyst, were employed. A Fe catalyst supported on MgO has been synthesized using the wet impregnation method followed by calcination. To compare the catalyst grain size and its distribution, the sample were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and BET specific surface area (SSA) measurement and X-ray photoelectron spectroscopy (XPS). XPS technique have utilized complementary to demonstrate the existence of chemical interaction between MgO support and Fe catalyst. Results revealed that the type of precursor used to prepare the support has a significant influence on the morphology of the support and the associated distribution of the Fe catalysts. The highest yield of MgFe2O4 phase was obtained using a pure MgO precursor which after calcination results in a homogenous distribution of nano-sized Fe particles over the support surface
