Effect of Rare Earth Element on Microstructure and Mechanical Properties of Mg-Sn-Ca Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 1558-1561
Author(s):  
Dae Guen Kim ◽  
Jae Seol Lee ◽  
Seul Ki Park ◽  
Young Mo Kim ◽  
Hyeon Taek Son ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Volume Fraction ◽  
Fine Needle ◽  
Microstructure Change ◽  
Microstructure And Mechanical Properties ◽  
Nd Addition ◽  
Mg2sn Phase

In the present work, the effect of Nd addition on microstructure change, precipitation behaviours and mechanical properties, of Mg-5Sn-3Ca based alloys were investigated. With increasing of Nd addition, size of the Mg-Sn-Ca ternary phases with fine needle shape (A-type) was decreased and volume fraction of these phase were increased. As Nd was increase from 0.5, 1.0 and 3.0 wt.%, size and volume fraction of Mg2Sn with coarse needle shape phase (B-type) was decreased. However, in 3.0 wt.% Nd containing alloy, size of these Mg2Sn phase was smaller than that of 0.5 and 1.0 wt% Nd addition alloy and volume fraction of these phase was decreased.

Microstructure and Mechanical Properties of Low Alloy Ultra-High Strength Steel Microalloyed with Cerium

2021 ◽  
Vol 871 ◽  
pp. 53-58
Author(s):  
Yue Yue Jiang ◽  
Zhao Dong Wang ◽  
Xiang Tao Deng ◽  
R.D.K. Misra
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Impact Energy ◽  
High Strength Steel ◽  
Earth Element ◽  
High Strength ◽  
Matrix Composition ◽  
Microstructure And Mechanical Properties ◽  
Ultra High Strength Steel

This study aims to investigate the influences of rare earth element cerium (Ce) on microstructure and mechanical properties of low alloy ultra-high strength steel. The strength, plasticity, and impact toughness of steels with 0.0367% Ce and without Ce were tested. The influence mechanism of Ce on the microstructure and mechanical properties were investigated by scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and electron back scattered diffraction (EBSD). The results showed that the addition of Ce improved the comprehensive mechanical properties of low alloy ultra-high strength steel. In particular, the plasticity and toughness were improved obviously. The addition of Ce increased the elongation from 9.47% to 10.49%, and the low-temperature impact energy from 50J to 58J. The elongation and impact energy increased by 10.77% and 16%, respectively. And the yield strength of all samples remained above 1400 MPa. The rare earth element Ce did not change the matrix composition phase which were martensite. However, the addition of Ce increased the proportion of high-angle grain boundary from 33.2% to 40.2%. In addition, the Ce make the inclusions denatured and hence spherical inclusion with small size can be obtained. The EDS results showed that rare earth and harmful elements P and O formed inclusions, which as a purifier for the molten steel and hindered the formation of the large-size composite inclusions.

Effect of Calcium on Solidification Behavior of Mg-Sn Based Alloys

2009 ◽  
Vol 620-622 ◽  
pp. 169-172 ◽  
Author(s):  
Dae Guen Kim ◽  
Hyeon Taek Son ◽  
Jae Seol Lee
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Solidification Behavior ◽  
Fine Needle ◽  
Microstructure Change ◽  
Ca Addition ◽  
Mg2sn Phase

The effect of Ca addition on microstructure change, precipitation behaviours and mechanical properties, in the present work, of Mg-Sn based alloys were investigated. With increasing of Ca additions, size of the Mg-Sn-Ca ternary phases (A-type) with fine needle shape was decreased and volume fraction of these phase were increased. As Ca was increase from 1 wt.%, 2 wt.%, size and volume fraction of Mg2Sn with coarse needle shape phase (B-type) was increased. However, in 3 wt.% Ca containing alloy, size of these Mg2Sn phase was smaller than that of 2 wt% Ca addition alloy and volume fraction of these phase was decreased.

Crystallization behavior, Al-Ce intermetallic formation, and microstructure refinement of near-eutectic Al–Si alloys by rare-earth element additions

2020 ◽  
Vol 111 (11) ◽  
pp. 938-952
Author(s):  
Bo Chi ◽  
Zhiming Shi ◽  
Cunquan Wang ◽  
Liming Wang ◽  
Hao Lian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Crystallization Behavior ◽  
Earth Element ◽  
Microstructural Refinement ◽  
Preferential Growth ◽  
Intermetallic Formation ◽  
The Matrix

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.

Effects of Y2O3 on Microstructure and Mechanical Properties of Laser Clad Coatings Reinforced by In Situ Synthesized TiB and TiC

2011 ◽  
Vol 675-677 ◽  
pp. 589-592 ◽  
Author(s):  
Jun Li ◽  
Zhi Shui Yu ◽  
Hui Ping Wang
Keyword(s):  
Mechanical Properties ◽  
Laser Cladding ◽  
Volume Fraction ◽  
Fine Needle ◽  
Microstructure And Mechanical Properties ◽  
Y2o3 Addition ◽  
Cracking Sensitivity

Titanium-based coatings reinforced by in situ synthesized TiB and TiC were deposited on Ti6Al4V by laser cladding. The effects of Y2O3 on microstructure and mechanical properties of the coatings were investigated. The coating without Y2O3 is mainly composed of a-Ti cellular dendrites and an eutecticum in which a large number of coarse and fine needle-shaped TiB and a few equiaxial TiC particles are homogeneously embedded. A small amount of Y2O3 addition can refine the microstructure by transforming a-Ti grains from cellular dendrites to columnar or equiaxial crystals, and can increase the volume fraction of the reinforcements. The addition of Y2O3 can also increase microhardness and reduce the cracking sensitivity of the coating.

Microstructure and Mechanical Properties of Rare-Earth Doped Si3N4 and Si3N4/SiC Ceramics

2010 ◽  
Vol 65 ◽  
pp. 78-85 ◽  
Author(s):  
Peter Tatarko ◽  
Štefánia Lojanová ◽  
Zdeněk Chlup ◽  
Ján Dusza ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Aspect Ratio ◽  
Ionic Radius ◽  
Earth Element ◽  
Rare Earth Oxide ◽  
Sic Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Significant Difference ◽  
Rare Earth Doped

Microstructure and mechanical properties of Si3N4 and Si3N4 + SiC nanocomposites sintered with rare-earth oxide additives (La2O3, Y2O3, Yb2O3 and Lu2O3) have been investigated. The composites exhibited smaller grain diameter compared to that of monolithic materials. The aspect ratio of β-Si3N4 grains increased with a decreasing ionic radius of rare-earth elements in the Si3N4 monoliths as well as in the Si3N4-SiC nanocomposites. The hardness of both systems increased with a decreasing ionic radius of rare-earth element. The fracture toughness of the materials with coarser microstructure and higher aspect ratio was higher due to the more frequent toughening mechanisms. No significant difference between strength values of monoliths and composites was observed and the strength in the composites was determined mainly by the present processing flaws. Significantly improved creep resistance was observed in the case of composites and for materials with smaller ionic radius of RE3+.

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