Study on Fracture of the Fibrous Monolith Cemented Carbide

2013 ◽  
Vol 815 ◽  
pp. 43-47
Author(s):  
Cun Guang Ding ◽  
Xue Quan Liu ◽  
Yi Li ◽  
Chang Hai Li ◽  
Nan Li ◽  
...  

A fibrous monolith cemented carbide with WC-6%Co as cell and WC-20%Co as cell boundaries was produced through hot co-extrusion process in this paper. The density, hardness, transverse rupture strength (TRS) and fracture toughness (KIc) of the fibrous monolith cemented carbide were tested, and the fracture and crack propagation were observed by metalloscope and Scanning Electron Microscope. The result shows fibrous monolith structure design could effectively improve the TRS and the KIc of WC/Co cemented carbide without a significant decrease of hardness. It is the reason of high transverse rupture strength and fracture toughness that WC-20%Co can absorb more fracture energy in order to slow, prevent, or deflect crack propagation, proved by metalloscope and scanning electron microscope.

2005 ◽  
Vol 19 (01n03) ◽  
pp. 577-579
Author(s):  
BIN CHEN ◽  
XIANG-HE PENG ◽  
JING-HONG FAN ◽  
WAN-LU WANG

A scanning electron microscope (SEM) observation on a Rufescens shell shows that the shell is a bio-ceramic composite consisting of aragonite sheets with nanometer scale and organic matrix. These nano-aragonite sheets are arranged in the shell in the form of helicoidal layup. The reason of the excellent fracture toughness of the shell is analyzed based on the maximal pullout force of the helicoidal layup of the aragonite sheets in the shell.


2009 ◽  
Vol 417-418 ◽  
pp. 521-524
Author(s):  
Michael Marx ◽  
Wolfgang Schäf ◽  
Markus T. Welsch ◽  
Horst Vehoff

From the emission of dislocations till short crack propagation fatigue is a local process determined by the microstructure. In this paper we present experiments based on refined applications of the scanning electron microscope and focused ion beam technique, which give detailed information about crack initiation and the interaction of short fatigue cracks with microstructural elements.


CrystEngComm ◽  
2013 ◽  
Vol 15 (17) ◽  
pp. 3305 ◽  
Author(s):  
Chongbin Wei ◽  
Xiaoyan Song ◽  
Jun Fu ◽  
Xuemei Liu ◽  
Haibin Wang ◽  
...  

2013 ◽  
Vol 750-752 ◽  
pp. 671-674
Author(s):  
Rong Hua Zhang ◽  
Yong An Zhang ◽  
Bao Hong Zhu

In this paper, the Al-8.5Fe-1.3V-1.7Si alloys were fabricated by spray forming and extrusion process. The microstructure and mechanical properties of the alloy were investigated by means of metallographic, scanning electron microscope and tensile test. The results indicate that the tensile strength of the extrued alloys can reach 353MPa, the yield strength 300MPa, elongation 19.12%, at room temperature. At 250°C, the tensile strength of the extrued alloys can reach 221MPa, the yield strength 208MPa, elongation 13.33%.


2013 ◽  
Vol 815 ◽  
pp. 233-239
Author(s):  
Xue Quan Liu ◽  
Cun Guang Ding ◽  
Chang Hai Li ◽  
Yi Li ◽  
Li Xin Li ◽  
...  

A fibrous monolith cemented carbide with WC-6Co as cell and WC-20Co as cell boundaries was produced through hot co-extrusion process in this paper. The density, hardness, bending strength and fracture toughness of the fibrous monolith cemented carbide were tested, and the fracture and crack propagation were observed by metalloscope and SEM. The results showed that the bending strength and fracture toughness of the fibrous monolith cemented carbides was remarkably improved 71.91% and 45.7% respectively, while the hardness was slightly decreased 1% compared with WC-6Co composites. It is the reason that the tougher shell WC-20Co with higher bending strength and fracture toughness can absorb more fracture energy, which can slow down and prevent the crack propagating from brittle core WC-6Co.


2011 ◽  
Vol 460-461 ◽  
pp. 652-655
Author(s):  
Bin Chen ◽  
Ji Luo ◽  
Quan Yuan

Scanning electron microscope (SEM) observation on a mature shankbone shows that the bone is a kind of bioceramic composite consisting of hydroxyapatite sheets and collagen protein matrix. The observation also shows that there are many holes in the bone and that the hydroxyapatite sheets near by these holes helicoidally round these holes forming a kind of helicoidally-rounded-hole microstructure (HRHM). The maximum pullout force of the HRHM is investigated and compared with that of non-helicoidally-rounded-hole microstructure (NHRHM). It shows that the HRHM could markedly increase the maximum pullout force of the hydroxyapatite sheets compared to the NHRHM and therefore enhance the fracture toughness of the bone.


2017 ◽  
Vol 726 ◽  
pp. 292-296 ◽  
Author(s):  
Peng Wu ◽  
Shao Cun Liu ◽  
Xiu Rong Jiang

The microstructures of the prepared Ti(C, N)-based cermets with various ratios of Co to Ni+Co were studied using X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Mechanical properties such as transverse rupture strength (TRS), fracture toughness (K1C) and hardness (HRA) were also measured. The results showed that when Ni was partly replaced by Co, the core size of hard particle and the thickness of rim phase changed. With the increasing of the ratio of Co to Ni+Co, the porosity of the cermets increased gradually, the fracture toughness of the cermets decreased gradually, the transverse rupture strength increased firstly and then decreased, the hardness changed slightly。When the ratio of Co to Ni+Co was 0.2, the cermets had better transverse rupture strength (TRS), which was characterized by fine grains and the moderate thickness of rim phase in the binder.


2010 ◽  
Vol 24 (01n02) ◽  
pp. 191-200
Author(s):  
B. CHEN ◽  
Q. YUAN ◽  
J. H. FAN ◽  
J. G. WANG ◽  
J. LUO

The observation of scanning electron microscope (SEM) showed that Tumblebug elytra consist of almost parallel upper and lower cuticles. Both of which are a kind of chitin-fiber-reinforced composite. There is a kind of chitin-fiber-reinforced composite pillars between the upper and lower cuticles, which support and connect the upper and lower cuticles uprightly. More careful observation showed that the chitin fibers in the pillars smoothly extend to the upper and lower composite cuticles forming a kind of fiber-continuous pillar-board composite (FCPBC) structure. Based on the observation, two kinds of pillar-board composite structure specimens, respective with continuous and discontinuous glass fibers, were fabricated with molding and felting processes. The rupture strengths of the two kinds of the specimens were tested and compared. It showed that the rupture strength of the specimens of the FCPBC structure is markedly larger than that of the specimens of the fiber-discontinuous pillar-board composite (FDPBC) structure. At last, the experimental result was analyzed for illumining the mechanism of the FCPBC structure in the enhancement of the strength.


2011 ◽  
Vol 467-469 ◽  
pp. 567-570
Author(s):  
Bin Chen ◽  
Ji Luo ◽  
Quan Yuan ◽  
Jing Hong Fan

Tooth is a kind of biomaterial in nature. It behaves favorable strength, stiffness and fracture toughness, which are closely related to its fine microstructure. The observation of scanning electron microscope (SEM) on a mature tooth shows that the tooth is a kind of natural bioceramic composite consisting of hydroxyapatite layers and collagen protein matrix. The observation also shows that the hydroxyapatite layers consist of long and thin hydroxyapatite sheets and that all the hydroxyapatite sheets are arranged in a kind of parallel distribution. The maximum pullout energy of the hydroxyapatite sheets, which is closely related to the fracture toughness of the tooth, is investigated based on the representative model of the parallel distribution. It shows that the long and thin shape as well as the parallel distribution of the hydroxyapatite sheets increase the maximum pullout energy and enhance the fracture toughness of the tooth.


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