نتایج جستجو برای: ultrafine grain

تعداد نتایج: 65667  

حمید رضا جاهد مطلق, , رامین جهادی نائینی, , محمد صدیقی, ,

In this paper, the effect of Equal Channel Angular Pressing (ECAP) process on the structure and mechanical properties of AM30 magnesium alloy was studied. The results showed a considerable effect of ECAP process on creating an ultrafine grain size structure. Scanning Electron Microscope indicated that the grain size dropped from 20.4 µm in the extruded form to 7.2 µm in the first pass and 3.9 µ...

Journal: :Materials transactions 2021

A laminated structured 2205 duplex stainless steel (DSS) with graded grain size was prepared via aluminothermic reaction and subsequent hot rolling deformation of 80% at 1000°C, its mechanical properties, strengthening toughening mechanism were studied. Our materials have extraordinary elongation 54% high tensile strength 990 MPa. The lamellar structure is characterized heterogeneous lamella au...

Journal: :Journal of Materials Research and Technology 2021

Journal: :Metallurgical and Materials Transactions A 2016

1998
K. Hono E. Abe T. Kumagai H. Harada

As Ti rich Ti-Al alloy shows ductile nature with the α2 + γ lamellar structure [1], the mechanism of microstructural evolution in Ti-Al alloys has attracted much interest. Since the lamellar structure is formed by the continuous cooling in industrial processes, cooling rate dependence of α → γ and α → α2 + γ transformations has been extensively studied by many researchers [2-5]. Wang et al. [2,...

Journal: :Materials research letters 2021

A nano/ultrafine grained immiscible Fe-Cu alloy was produced using selective laser melting (SLM) with an average grain size of 250?nm and many 50–100?nm, the finest ever achieved additive man...

Abdoulmajid Eslami, Behzad Sadeghian, Fathallah Karimzadeh Reihane Nafar Dehsorkhi, Soheil Sabooni

In the present study, an ultrafine grained (UFG) 304L stainless steel with the average grain size of 300 nm was produced by a combination of cold rolling and annealing. Weldability of the UFG sample was studied by Nd: YAG laser welding under different welding conditions. Taguchi experimental design was used to optimize the effect of frequency, welding time, laser current and laser pulse duratio...

A review on the microstructural evolution in magnesium alloys during severe plastic deformation waspresented. The challenges deserved to achieve ultrafine/ nanostructured magnesium were discussed.The characteristics of the processed materials are influenced by three main factors, including i)difficult processing at low temperatures, ii) high temperature processing and the occurrence ofdynamic r...

2015
Hailiang Yu A. Kiet Tieu Cheng Lu Xiong Liu Mao Liu Ajit Godbole Charlie Kong Qinghua Qin

It is well known that when coarse-grained metals undergo severe plastic deformation to be transformed into nano-grained metals, their ductility is reduced. However, there are no ductile fracture criteria developed based on grain refinement. In this paper, we propose a new relationship between ductile fracture and grain refinement during deformation, considering factors besides void nucleation a...

2010
ZONGHOON LEE VELIMIR RADMILOVIC BYUNGMIN AHN ENRIQUE J. LAVERNIA STEVEN R. NUTT

The tensile fractures of ultrafine-grained (UFG) Al-Mg alloy with a bimodal grain size were investigated at the microand macroscale using transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with focused ion beam (FIB), and optical microscopy. The nanoscale voids and crack behaviors near the tensile fracture surfaces were revealed in various scale ranges and provi...

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