scholarly journals Effects of Yb Addition on the Microstructure and Mechanical Properties of As-Cast ADC12 Alloy

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 108 ◽  
Author(s):  
Junjie Xiong ◽  
Hong Yan ◽  
Songgen Zhong ◽  
Minzhu Bi

The effects of addition of different amounts of rare earth ytterbium (Yb) on the microstructure and mechanical properties of the casting ADC12 alloy were investigated by mechanical properties testing and microstructure observation. The results indicate that Yb modification had a big influence on the microstructure and properties of the as-cast alloy. The optimum level of Yb content was 0.8 wt %. The coarse dendritic primary α-Al phases were fully refined, leading to the decreasing of the secondary dendrite arm spacing. The morphology of eutectic silicon phases changed from acicular into short rod-like and even granular. There was a structural transformation of β-Fe phases from massive to small rod-shaped morphology. Additionally, the tensile strength, elongation, and microhardness were 267.9 MPa, 4.2%, and 107.3 HV, respectively, increases of 55.4, 121.1, and 41.4%, respectively, compared with the matrix alloy. Fractographic examinations reveal that mainly ductile fracture for Yb addition of 0.8 wt %. The fracture appearances matched the tendency of the tensile properties. Furthermore, the addition of Yb can generate a rare earth phase consisting of the three elements of Al, Si, Yb, with some small iron-rich phases attached around the rare earth phase.

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.


1994 ◽  
Vol 364 ◽  
Author(s):  
W. M. Yin ◽  
J. T. Guo ◽  
S. H. Wang ◽  
H. Li ◽  
M. H. Tan ◽  
...  

AbstractThe microstructure and mechanical properties of Ni3Al-based composites reinforced with TiC particles have been investigated. The composites, which contained 2, 6, 10 vol.%TiC particulate reinforcement, were fabricated by solidification processing method. The matrix alloy selected for this study was the advanced nickel-aluminide (Ni-16Al-8Cr-1Zr-0.8Mo-0.04B at.%).The optical micrographs revealed that the carbides in the composites distributed uniformly in the martix and appeared as fairly equiaxed particles. SEM observation showed that the interface between TiC and matrix is quite smooth, sharp and free of any phase. The test results indicated that the hardness was increased with increasing volume fraction of TiC particles at ambient temperature, and the composites exhibited higher hardness after 1100°C × 8h heat treatment. The yield strength has been improved due to reinforcement by the TiC particles at ambient and elevated temperature, but their ductility was reduced obviously. From SEM fractography, it could be seen that tensile failure occurred at the matrix / particulate interface.


2011 ◽  
Vol 189-193 ◽  
pp. 4014-4017 ◽  
Author(s):  
Wen Min Zhao ◽  
Xiao Fei Jia ◽  
Zhi Feng Wang ◽  
Zhi Gao Yin ◽  
Guo Yuan Xiong

The tube-shaped parts of A356 alloy were deformed from 0% to 83% by spinning process. The microstructure and mechanical properties of A356 alloy were discussed. The results showed that as the wall thickness reduction increases, the dendrite cells of cast alloy are lengthened gradually and the average Secondary Dendrite Arm Spacing (SDAS) is reduced from 37.2μm to 23μm and eutectic silicon particles are distributed orderly along the spinning direction. The coarse acicular β-Al5FeSi is broken into many sections, and its length is reduced from 37.5μm to 12.5μm in the cross-section. The tensile strength and elongation exhibit a strong dependence upon the variation in wall thickness, with a parabolic relationship. The tensile fractured surface of parts with deformation ratio above 35% exhibits many equiaxial dimples, with intergranular ductile fracture mode.


2015 ◽  
Vol 1112 ◽  
pp. 462-465 ◽  
Author(s):  
Oknovia Susanti ◽  
Sri Harjanto ◽  
Myrna A. Mochtar

Mg-1.6 Gd alloy ingot were prepared by hot extrusion. The extruded alloy exhibits the recrystallised grain size and excellent mechanical properties. The aim of this study is to explore the microstructure and mechanical properties of extruded Mg-1.6 Gd to be used as implant. Extrusion was performed at temperatures of 400°C, 450 °C, 500°C and 550°C with a speed of 1mm/s and extrusion ratio of 30%. Tension and hardness testing were carried out on samples taken from extruded rod of Mg-Gd alloy. Microstructure observation revealed that all extruded alloy specimens constitued of finer grain size (~14 um) compared to that of the as-cast alloy (> 500 um) as the result of full recrystallization occured at 400 °C. The grain size increased larger with an increase temperature and the peak value is 25mm at temperature of 550 °C. Hardness of the alloy decreased as the extrusion temperature increased from 48.7 HV at 400 °C to 42 HV at 550 °C which is associated with the change in the grain size. Tensile strengths were not apparently affected by the temperature change, however, it was observed that the tensile and yield strengths dropped at 500 °C. Meanwhile, the elongation decreased with increasing temperature which reached 24 % at the lowest temperature. Detailed explaination of the relationship of microstructure and mechanical properties is discussed in this paper.


2014 ◽  
Vol 788 ◽  
pp. 58-63 ◽  
Author(s):  
Shi Bo Fan ◽  
Jian Peng ◽  
Ming Zhou ◽  
Kai Cui ◽  
Quan Li

In this paper, the effects of Ce addition on the microstructure and mechanical properties of the cast and extruded ZM21 magnesium alloy were investigated by OM, XRD, SEM and tensile test at room temperature. It was found that with increase of Ce content, the Mg-Ce and Mg-Zn phases which gather in dendritic gap as second phases increase gradually, and form a network structure finally, which becomes thicker due to serious segregation. Meanwhile, Most of Ce in the extruded ZM21 magnesium alloy is in the forms of second phases, and is broken and dispersed in the matrix alloy during the plastic deformation. With the increase of Ce content, the quantity of the second phase increases, and both the tensile strength and the elongation of ZM21 alloys decrease firstly and then increase. When the content of Ce is 0.57%, the elongation barely reaches the level of ZM21 magnesium alloy. After extrusion, both the tensile and yield strength have been greatly improved.


2007 ◽  
Vol 546-549 ◽  
pp. 503-507
Author(s):  
Le Ping Bu ◽  
Shunsuke Tanaka ◽  
Masayuki Tsushida ◽  
Shinji Ando ◽  
Hideki Tonda

In the present study, the conventional process of Compo-casting was carried and the microstructural and mechanical propertied were then investigated. The matrix alloy used was Mg- 6Al, and B2O3 was added into Mg-Al alloys was investigated at two levels of 3 and 6wt%. The other experimental materials were NaCl and CaCl2. The microstructures were of the samples analyzed with Optical Microscopy, SEM and XRD, and the mechanical properties were determined by micro-hardness and tensile test. The results showed that the mechanical properties of Mg- 6Al- 3B2O3- 1NaCl- 1CaCl2 increased and the microstructure was satisfactory, for a cast alloy, i.e.the tensile strength was 175MPa.


2020 ◽  
Vol 59 (1) ◽  
pp. 340-351
Author(s):  
Lin Yinghua ◽  
Ping Xuelong ◽  
Kuang Jiacai ◽  
Deng Yingjun

AbstractNi-based alloy coatings prepared by laser cladding has high bonding strength, excellent wear resistance and corrosion resistance. The mechanical properties of coatings can be further improved by changing the composition of alloy powders. This paper reviewed the improved microstructure and mechanical properties of Ni-based composite coatings by hard particles, single element and rare earth elements. The problems that need to be solved for the particle-reinforced nickel-based alloy coatings are pointed out. The prospects of the research are also discussed.


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.


2019 ◽  
Vol 38 (2019) ◽  
pp. 404-410 ◽  
Author(s):  
Weijuan Li ◽  
Haijian Xu ◽  
Xiaochun Sha ◽  
Jingsong Meng ◽  
Zhaodong Wang

AbstractIn this study, oxide dispersion strengthened (ODS) ferritic steels with nominal composition of Fe–14Cr–2W–0.35Y2O3 (14Cr non Zr-ODS) and Fe–14Cr–2W–0.3Zr–0.35Y2O3 (14Cr–Zr-ODS) were fabricated by mechanical alloying (MA) and hot isostatic pressing (HIP) technique to explore the impact of Zr addition on the microstructure and mechanical properties of 14Cr-ODS steels. Microstructure characterization revealed that Zr addition led to the formation of finer oxides, which was identified as Y4Zr3O12, with denser dispersion in the matrix. The ultimate tensile strength (UTS) of the non Zr-ODS steel is about 1201 MPa, but UTS of the Zr-ODS steel increases to1372 MPa, indicating the enhancement of mechanical properties by Zr addition.


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