Microstructure and Mechanical Properties of an Mg-Zn-Zr Alloy Modified by Rare Earth of Erbium

2009 ◽  
Vol 610-613 ◽  
pp. 810-814 ◽  
Author(s):  
Jing Zhang ◽  
Xu Feng Zhang ◽  
Fu Sheng Pan ◽  
Chuan Pu Liu ◽  
Qu Bo He

The microstructures, mechanical properties, and formability of an Mg-1.5Zn-0.1Zr alloy with rare earth element of Erbium addition have been examined by using optical microscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy, and thermal mechanical testing. The results showed that Erbium combined with Mg and impurity elements forming small particles dispersed on the matrix. Therm-mechanical simulation in the temperature range from 250°C to 400°C and strain rate from 0.1 to 1.0 indicated that the flow stress decreases with the increase of the temperature and the decrease of the strain rate. Sheet samples were prepared through ingot casting, hot rolling, cold rolling, and intermediate annealing. Remarkable grain size refinement was realized through recrystallization during the rolling process. Good combination of strength and ductility was achieved by applying intermediate annealing before the very last cold rolling. Further improvement of ductility and formability could be obtained by conducting proper heat treatment on the finishing cold-rolled sheets.

Author(s):  
Bo Chi ◽  
Zhiming Shi ◽  
Cunquan Wang ◽  
Liming Wang ◽  
Hao Lian ◽  
...  

Abstract Near-eutectic Al-Si alloys have low strength and high brittleness because of the presence of many eutectic b-Si flakes, needle-like Al-Fe-Si intermetallics, and coarse α-Al grains. This study disclosed the effects of cerium-rich RE (rare earth) element modification on orientation characters of crystals, formation of Al-Ce compounds, and microstructural refinement to improve the microstructure and mechanical properties of the alloys. The RE addition depressed preferential growth along the close-packed and/or sub-closepacked planes and promoted growth along the non-closepacked planes, in which La and other elements were dissolved into needle-like Al11Ce3 phase. When the temperature decreased, Al11Ce3 was preferentially crystallized from the melts and then devitrified by attaching to the surface of β-Al5FeSi needles. Moreover, many small Al11Ce3 particles were precipitated in the matrix and on the Si surface by a T6 heat treatment. Eutectic β-Si phases were constructed into discontinuous networks, short rods, and even particles by RE additions, which were further transformed into fine nodules following the T6 treatment. α-Al grains and primary β-Al5FeSi needles were simultaneously refined. The addition of 1.0 wt.% REs and subsequent T6 treatment yielded the highest tensile strength, elongation, and hardness of the alloy.


2014 ◽  
Vol 875-877 ◽  
pp. 63-67 ◽  
Author(s):  
Dinh van Hai ◽  
Nguyen Trong Giang

In this work, ECAP technique was combined with cold rolling process in order to enhance mechanical properties and microstructure of pure Titanium. Coarse grain (CG) Titanium with original grain size of 150 μm had been pressed by ECAP at 425oC by 4, 8 and 12 passes, respectively. This process then was followed by rolling at room temperature with 35%, 55%, and 75% rolling strains. After two steps, mechanical properties such as strength, hardness and microstructure of processed Titanium have been measured. The result indicated significant effect of cold rolling on tensile strength, hardness and microstructure of ECAP-Titanium.


POROS ◽  
2017 ◽  
Vol 12 (1) ◽  
pp. 58
Author(s):  
Riyan Sanjaya ◽  
Eddy S Siradj

Abstract: The research was conducted because of the many industries that use CuZn 70/30 as a raw material in industrialization. CuZn 70/30 was studied to obtain the strong mechanical properties of brass. Research CuZn 70/30 was evaluated using a process of heating of about 6150 ± 50C and then held for 90 minutes. The next process is the process of cold rolling by using a variety of reduction and then tested by using a Vickers hardness testing, tensile testing, observation of the microstructure. The result of this research is a fine microstructure (below 10 μm), hardness (HV 211.67). Tensile test also conducted to get how much resistance CuZn 70/30 to resist the pull. The cold rolling process causing the decrease the mechanical properties and also increase the plastic properties of the brass. 


2010 ◽  
Vol 150-151 ◽  
pp. 815-820
Author(s):  
Shu Jun Ji ◽  
Xue Yi Guo ◽  
Jian Xiong Dong ◽  
Peng Su

Using corundum, quartz, kaoline, etc, as base components and CeO2-rich mixed rare earth as modifier, foam ceramics were fabricated adopting the organic foam impregnation process. The mixed rare earth addition had much improving effects on the matrix mechanical properties owing to much glass phase and acerate mullite growing. While 3wt% was considered to be the optimal addition, in this case, homogeneous and compact ceramic microstructure with maximal glass condensation and minimal porosity formed, with the matrix compressive strength and the flexural strength at room temperature reached 0.87MPa and 0.66MPa respectively, which were 52.6% and 73.7% higher than the original samples respectively. As the mixed rare earth addition exceeded further, the compressive strength increased slowly and the flexural strength descended gradually. XRD and SEM were used to structure strengthening mechanism analysis.


2011 ◽  
Vol 239-242 ◽  
pp. 352-355
Author(s):  
Quan An Li ◽  
Qing Zhang ◽  
Chang Qing Li ◽  
Yao Gui Wang

The effects of 2-12 wt.% Y addition on the microstructure and mechanical properties of as-cast Mg-Y binary alloys have been investigated. The results show that proper content of rare earth Y addition can obviously refine the grains and form high melting point Mg24Y5 phases in the matrix, and improve the microstructure and mechanical properties of the alloys. At room temperature, the optimum combination of ultimate tensile strength and elongation, 195MPa and 7.5%, is obtained in Mg-10 wt.% Y alloy.


Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1337 ◽  
Author(s):  
Paul Lohmuller ◽  
Laurent Peltier ◽  
Alain Hazotte ◽  
Julien Zollinger ◽  
Pascal Laheurte ◽  
...  

The variations of the mechanical properties of the CoCrFeMnNi high entropy alloy (HEA) during groove cold rolling process were investigated with the aim of understanding their correlation relationships with the crystallographic texture. Our study revealed divergences in the variations of the microhardness and yield strength measured from samples deformed by groove cold rolling and conventional cold rolling processes. The crystallographic texture analyzed by electron back scattered diffraction (EBSD) revealed a hybrid texture between those obtained by conventional rolling and drawing processes. Though the groove cold rolling process induced a marked strengthening effect in the CoCrFeMnNi HEA, the mechanical properties were also characterized by an unusual decrease of the Young’s modulus as the applied groove cold rolled deformation increased up to about 0.5 before reaching a stabilized value. This decrease of the Young’s modulus was attributed to the increased density of mobile dislocations induced by work hardening during groove cold rolling processing.


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