Microstructural and Mechanical Properties of Er2O3-ZrO2 Ceramics with Different Er2O3 Contents

2012 ◽  
Vol 31 (6) ◽  
pp. 701-706 ◽  
Author(s):  
Süleyman Tekeli ◽  
Bülent Aktaş ◽  
Mustafa Küçüktüvek
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
Lattice Parameter ◽  
Erbium Oxide ◽  
Cubic Crystal ◽  
Hardness Tester ◽  
Different Temperatures

AbstractIn this study, the effect of erbium oxide (Er2O3) addition on the microstructure, sinterability and mechanical properties of cubic zirconia (c-ZrO2) was investigated. 0–15 wt% Er2O3 and c-ZrO2 powders were mixed by means of colloidal processing and the specimens were sintered at different temperatures for 1 hour. The XRD results showed the existence of cubic crystal structure in all specimens. The lattice parameter of the specimens decreased with increasing Er2O3 addition up to 10 wt% and remained unchanged after this amount. The grain size of the Er2O3 doped c-ZrO2 specimens dropped up to 5 wt% Er2O3 addition and stayed almost unchanged at higher Er2O3 contents. Both hardness and fracture toughness measurements were done using Vickers hardness tester. The fracture toughness values of the undoped, 1, 5, 10 and 15 wt% Er2O3 doped c-ZrO2specimens were found to be 1.64 MPam1/2, 1.77 MPam1/2, 2.06 MPam1/2, 2.57 MPam1/2 and 2.31 MPam1/2 respectively.

scholarly journals Influence of Vacuum Heat Treatments on Microstructure and Mechanical Properties of M35 High Speed Steel

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 643
Author(s):  
Chiara Soffritti ◽  
Annalisa Fortini ◽  
Ramona Sola ◽  
Elettra Fabbri ◽  
Mattia Merlin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
High Speed ◽  
High Speed Steel ◽  
Plane Strain Fracture Toughness ◽  
Secondary Carbides ◽  
Heat Treated ◽  
Strain Fracture

Towards the end of the last century, vacuum heat treatment of high speed steels was increasingly used in the fabrication of precision cutting tools. This study investigates the influence of vacuum heat treatments at different pressures of quenching gas on the microstructure and mechanical properties of taps made of M35 high speed steel. Taps were characterized by optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, apparent grain size and Vickers hardness measurements, and scratch tests. Failure analysis after tapping tests was also performed to determine the main fracture mechanisms. For all taps, the results showed that microstructures and the values of characteristics of secondary carbides, retained austenite, apparent grain size and Vickers hardness were comparable to previously reported ones for vacuum heat treated high speed steels. For taps vacuum heat treated at six bar, the highest plane strain fracture toughness was due to a higher content of finer small secondary carbides. In contrast, the lowest plane strain fracture toughness of taps vacuum heat treated at eight bar may be due to an excessive amount of finer small secondary carbides, which may provide a preferential path for crack propagation. Finally, the predominant fracture mechanism of taps was quasi-cleavage.

Simultaneous Synthesis and Sintering of Al2O3/Mo2N Composites Using Capsule-Free Nitrogen Hot Isostatic Pressing and their Characterization

2010 ◽  
Vol 62 ◽  
pp. 197-202
Author(s):  
Hirota Ken ◽  
Takaoka Katsuya ◽  
Murase Yasushi ◽  
Kato Masaki
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Hot Isostatic Pressing ◽  
Isostatic Pressing ◽  
Simultaneous Synthesis ◽  
Powder Compacts ◽  
Al2o3 Matrix

Synthesis of dense materials with the compositions of Al2O3/Mo2N=100/0 ~ 40/60 vol% has been attempted directly from Al2O3/Mo mixed raw powder compacts using capsule-free N2 hot isostatic pressing (HIP). During HIPing [1500°C/(16~20)MPa]/1h], solid/gas reaction between Mo and N2 was introduced to form Mo2N. Most sintered composites consisting of only Al2O3 and Mo2N phases reached a higher relative density than 98.0% with closed pores nevertheless capsule-free HIPing. Distribution of Mo2N particles just formed suppressed the grain growth of Al2O3 during sintering. Mechanical properties, such as bending strength (Σb), Vickers hardness (HV), fracture toughness (K1C), and other properties have been evaluated as a function of their compositions. The best mechanical values of Σb (c.a. 573 MPa), HV (c.a. 20.3 GPa) and K1C (c.a. 5.00 MPa･m1/2) were attained at the composition of Al2O3/Mo2N=90/10 vol%, due to a high density (98.6%) and small grain size of Al2O3 matrix (Gs c.a. 4.70 μm). Further addition of Mo2N reduced the sinterability of matrix grains, resulting in low densities of around 90% at the 40/60 vol% composition.

Effect of (Ni,Mo) and (W,Ti)C on the Microstructure and Mechanical Properties of TiB2 Ceramic Tool Materials

2012 ◽  
Vol 723 ◽  
pp. 233-237 ◽  
Author(s):  
Tong Chun Yang ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou ◽  
Hong Tao Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Flexural Strength ◽  
Grain Growth ◽  
Vickers Hardness ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties

TiB2-(W,Ti)C composites with (Ni,Mo) as sintering additive have been fabricated by hot-pressing technique, and the microstructure and mechanical properties of the composites have been investigated. (Ni,Mo) promotes grain growth of the composites. In the case of 7vol.% (Ni,Mo), the grain size decreases consistently with an increase in the content of (W,Ti)C. When the proper content of (W,Ti)C is added to TiB2 composites, the growth of matrix grains is inhibited and the mechanical properties of the composites are improved. The best mechanical properties of the composites are 1084.13MPa for three-point flexural strength, 7.80MPa•m 1/2 for fracture toughness and 17.92GPa for Vickers hardness.

Densification Behaviour and Mechanical Properties on MgO Doped Zirconia Toughened Alumina (ZTA) Prepared by Two-Stage Sintering

2021 ◽  
Vol 1030 ◽  
pp. 3-10
Author(s):  
Teow Hsien Loong ◽  
Ananthan Soosai ◽  
Suresh Muniandy
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Total Hip Arthroplasty ◽  
Young’S Modulus ◽  
Vickers Hardness ◽  
Young's Modulus ◽  
Two Stage ◽  
Positive Effect ◽  
Zirconia Toughened Alumina

The effect of doping small amounts of Magnesium Oxide ranging between 0 to 1 vol% on Zirconia Toughened Alumina (ZTA) composites which is one of main biomaterial used for production of total hip arthroplasty were investigated. The samples were produced via conventional two-stage sintering with T1 varies between 1450°C and 1550°C with heating rate of 20°C/min. The samples were then rapid cooled to T2 set at 1400°C with holding time of 12 hours. The microstructural and mechanical properties of the two-stage sintered ZTA are then investigated to determine the feasibility of MgO addition. Combination of two-stage sintering at T1 above 1500 and also small amount of MgO up to 0.5 vol% were shown to have positive effect on ZTA which exhibited improvement on its grain size, mechanical properties such as Vickers hardness, Young’s modulus and fracture toughness compared to undoped ZTA composites. The sample with 0.5 vol% MgO addition sintered at T1 of 1500°C and T2 1400°C was able to achieve Vickers hardness of 19.6 GPa, Young’s modulus of 408 GPa and fracture toughness of 6.8 MPam1/2 without significant grain growth compared to undoped ZTA composites.

Influence of Al2O3 Addition on the Microstructure and Mechanical Properties of Pressureless Sintered Ce-TZP

2005 ◽  
Vol 492-493 ◽  
pp. 783-0 ◽  
Author(s):  
Shui Gen Huang ◽  
Lin Li ◽  
Jef Vleugels ◽  
Pei Ling Wang ◽  
Omer Van der Biest
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Grain Growth ◽  
Vickers Hardness ◽  
Good Combination ◽  
Al2o3 Content ◽  
Pressureless Sintering ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties

Mixtures of 12 mol% CeO2-stabilised ZrO2 with 5 to 20 wt % Al2O3 were prepared and densified through pressureless sintering in air at 1450° C for 1 to 4 h. The influence of the Al2O3 content and sintering time on the phase constitution, microstructure and mechanical properties of the as-sintered composites were investigated. Fully dense Ce-TZP/Al2O3 ceramics with a good combination of hardness and fracture toughness can be obtained by pressureless sintering in air for only 1 h. The addition of Al2O3 to Ce-TZP improves the mechanical properties and suppresses ZrO2 grain growth. The average ZrO2 grain size increases with increasing sintering time and decreasing Al2O3 content. This leads to an increase in toughness. An excellent fracture toughness of 14.3 MPam1/2 in combination with a Vickers hardness of 9.14 GPa was obtained for 12 mol % CeO2-TZP with 5 wt % Al2O3, sintered for 4 h.

scholarly journals KETANGGUHAN RETAK, KEKERASAN DAN KONDUKTIVITAS IONIK CSZ SEBAGAI ELEKROLIT PADAT SOFC DENGAN PENAMBAHAN CuO

2015 ◽  
Vol 16 (2) ◽  
pp. 85
Author(s):  
Ila Lailatun Sholihah ◽  
Dani Gustaman Syarif ◽  
Andhy Setiawan
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Ionic Conductivity ◽  
Solid Electrolyte ◽  
Optical Microscope ◽  
Crystal Structure Analysis ◽  
Cubic Phase ◽  
Hardness Tester ◽  
Lcr Meter

ABSTRAK KETANGGUHAN RETAK, KEKERASAN DAN KONDUKTIVITAS IONIK CSZ SEBAGAI ELEKROLIT PADAT SOFC DENGAN PENAMBAHAN CuO. Penelitian mengenai pengaruh penambahan CuO terhadap konduktivitas ionik, kekerasan dan ketangguhan retak CSZ sebagai elektrolit padat SOFC telah dilakukan. CSZ didoping dengan CuO dengan konsentrasi 0, 1, dan 2 % berat. Pelet CSZ yang didoping CuO dikompaksi dengan tekanan 4 ton/cm2 dan disinter pada suhu 1475 0C selama 3 jam. Konduktivitas ionik diukur dengan menggunakan alat LCR meter. Konduktivitas ionik CSZ dengan doping 0, 1, dan 2 % berat CuO adalah 0,063 mS/cm; 0,110 mS/cm; dan 0,082 mS/cm. Kekerasan dan ketangguhan retak diukur dengan metode vickers menggunakan alat uji keras Zwick. Hasil kekerasan vickers berturut-turut 9,9 GPa; 12,1 GPa; dan 10,5 GPa, dan ketangguhan retak berturut-turut 1,61 MPa/m0,5; 1,85 MPa/m0,5; dan 1,54 MPa/m0,5. Analisis struktur kristal dilakukan dengan menggunakan XRD. Hasil analisis menunjukkan bahwa keramik yang dibuat berfase kubik FCC. Analisis struktur mikro dengan menggunakan mikroskop optik menunjukkan bertambahnya ukuran butir dengan peningkatan 1% berat CuO. Secara keseluruhan penambahan CuO dengan konsentrasi 1% berat dapat memperbaiki sifat listrik dan sifat mekanik CSZ sebagai elektrolit padat. ABSTRACT FRACTURE TOUGHNESS, HARDNESS AND IONIC CONDUCTIVITY OF CSZ AS SOLID ELECTROLYTE WITH ADDITION OF CuO. A research on effect of CuO addition on ionic conductivity, hardness and fracture toughness of CSZ as solid electrolyte had been conducted. CSZ was doped with 0, 1, and 2 wt % CuO. Pellets of CuO doped CSZ had been prepared by pressing with pressure of 4 ton/cm2 and sintered at 1475oC for 3 hours. Ionic conductivity was measured by means of LCR meter. Ionic conductivity values of CSZ with doped 0, 1, and 2 % CuO were 0.063 mS/cm, 0.110 mS/cm, and 0.082 mS/cm. Hardness and fracture toughness were measured by vickers method using a hardness tester Zwick. The measured vickerss hardness were 9.9 GPa, 12.1 GPa and 10.5 GPa, and fracture toughness were 1.61 MPa/m0,5, 1.85 MPa/m0,5, and 1.54 MPa/m0,5. Crystal structure analysis was done by using XRD. The analysis result showed that the prepared ceramics have cubic phase of FCC. Microstructure analysis by using an optical microscope showed that grain size increased with the increased of 1 wt % CuO. The addition of CuO at conscentration of 1 wt % can improve the electrical and mechanical properties of CSZ as solid electrolyte.

scholarly journals Properties of TiC and TiN Reinforced Alumina–Zirconia Composites Sintered with Spark Plasma Technique

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1220 ◽  
Author(s):  
Magdalena Szutkowska ◽  
Sławomir Cygan ◽  
Marcin Podsiadło ◽  
Jolanta Laszkiewicz-Łukasik ◽  
Jolanta Cyboroń ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Vickers Hardness ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Plasma Sintering ◽  
Different Temperatures ◽  
Spark Plasma ◽  
New Type ◽  
Diffraction Patterns

In this paper, Al2O3–ZrO2 composites with an addition of 20 wt% TiN and 10 wt% TiC were modified. The addition of zirconia in a range from 2 to 5 wt% of the monoclinic phase and 10 wt% of Y2O3 stabilised ZrO2 affected the mechanical properties of the composites. A new type of sintering technique—the spark plasma sintering (SPS) method—within a temperature range from 1575 °C to 1675 °C, was used. Vickers hardness, apparent density, wear resistance and indentation fracture toughness KIC(HV) were evaluated at room temperature. An increase of the sintering temperature resulted in an improvement of Vickers hardness and an increase of the fracture toughness of the tested composites. The tribological properties of the samples were tested using the ball-on-disc method. The friction coefficient was in a range from 0.31 to 0.55, depending on the sintering temperature. An enhancement of the specific wear rate was dependent on the sintering temperature. The mechanical properties of the samples sintered by pressureless sintering (PS) were compared. X-ray diffraction patterns were presented in order to determine the phase composition. SEM microstructure of the tested composites sintered at different temperatures was observed.

scholarly journals Microstructure and Properties of Ultrafine Cemented Carbides Prepared by Microwave Sintering of Nanocomposites

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 507
Author(s):  
Yanju Qian ◽  
Zhiwei Zhao
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Raw Material ◽  
Cemented Carbides ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

Ultrafine cemented carbides were prepared by microwave sintering, using WC-V8C7-Cr3C2-Co nanocomposites as a raw material. The effects of sintering temperature and holding time on the microstructure and mechanical properties of cemented carbides were studied. The results show that the ultrafine cemented carbides prepared at 1300 °C for 60 min have good mechanical properties and a good microstructure. The relative density, Vickers hardness, and fracture toughness of the specimen reach the maximum values of 99.79%, 1842 kg/mm2 and 12.6 MPa·m1/2, respectively. Tungsten carbide (WC) grains are fine and uniformly distributed, with an average grain size of 300–500 nm. The combination of nanocomposites, secondary pressing, and microwave sintering can significantly reduce the sintering temperature and inhibit the growth of WC grains, thus producing superfine cemented carbides with good microstructure and mechanical properties.

scholarly journals Densification and Mechanical Properties of Alumina Ceramics via Two-Step Sintering With Different Holding Times

2021 ◽  
Vol 6 (4) ◽  
pp. 299-304
Author(s):  
Anis Syufina Mohammad Saufi ◽  
Ramesh Singh ◽  
K. Y. Sara Lee ◽  
Tao Wu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Relative Density ◽  
Grain Growth ◽  
Vickers Hardness ◽  
Holding Time ◽  
Alumina Ceramics ◽  
Conventional Sintering ◽  
Viable Approach

The densification and mechanical properties of alumina ceramics were investigated via two-step sintering (TSS) with different holding time. The alumina ceramics were sintered at 1450 °C for 1 min during the first stage, followed by sintering at 1350 °C with different holding times (2-24h). Conventional sintering (CS) was also performed on the alumina ceramics at 1450 °C for 2 h for comparison purpose. It was found that dense alumina with a relative density above 98% could be attained when TSS with a holding time of more than 12 h. The samples exhibited Vickers hardness between 5-8 GPa and fracture toughness of about 6 MPa.m1/2. In contrast, conventional sintered alumina yielded low relative density (85%), large grain size (2 μm), low Vickers hardness (4.23 GPa) and fracture toughness (4.73 MPa.m1/2). This study revealed that TSS is a viable approach in aiding densification, suppressing grain growth, and improving the mechanical properties of alumina ceramics.

Study on Mechanical Properties and Toughening Mechanism of MWCNTs/Ti(C, N) Cermets-Based Composites

2013 ◽  
Vol 544 ◽  
pp. 291-294
Author(s):  
Shuo Qi Liu ◽  
Wei Liang Liu
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Residual Stress ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Crack Deflection ◽  
Toughening Mechanism ◽  
Hot Pressing Sintering ◽  
Sintering Method

MWCNTs/Ti(C, N) cermets-based composites were prepared by vacuum hot-pressing sintering method. The mechanical properties of samples were examined. XRD and SEM were used to investigate the crystal structure of the composites and microstructure of fractures surface, respectively. The toughening mechanism of composites was discussed particularly. The experimental results showed that the optimum comprehensive mechanical properties of samples were obtained by adding 1wt% MWCNTs in the composites. The bending strength, Vickers hardness and fracture toughness of the composites were 1275.14MPa, 22.75GPa and 10.60MPa•m1/2, respectively, which were improved by 16.89%, 17.15% and 25.59%, respectively, compared to the Ti(C, N)-based cermets without MWCNTs. Bridging and pulling out of MWCNTs, crack deflection, residual stress toughening and micro-voids toughening were attributed to the toughening mechanism of the composites.

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