The Effects of Grain Size on Strength, Fracture Toughness, and Static Fatigue Crack Growth in Alumina

1992 ◽  
pp. 125-136 ◽  
Author(s):  
Nobuyuki Miyahara ◽  
Yoshiharu Mutoh ◽  
Kouhei Yamaishi ◽  
Keizo Uematsu ◽  
Makoto Inoue
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Static Fatigue

scholarly journals Comparison of Microstructure and Mechanical Properties of High Strength and Toughness Ship Plate Steel

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5886
Author(s):  
Dong Wang ◽  
Peng Zhang ◽  
Xingdong Peng ◽  
Ling Yan ◽  
Guanglong Li
Keyword(s):  
Fracture Toughness ◽  
Growth Rate ◽  
Grain Size ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Impact Toughness ◽  
Crack Growth ◽  
Plate Steel ◽  
The Relationship

E36 ship plate steel was, respectively, produced by as rolling and normalizing process (ARNP), and EH36 and FH36 ship plate steel was produced by the thermo-mechanical control process (TMCP) with low carbon and multi-element micro-alloying. The microstructure of the three grades of ship plate steel was composed of ferrite, pearlite, and carbides at room temperature. The average grain size on 1/4 width sections (i.e., longitudinal sections) of the three grades of ship plate steel was, respectively, 5.4 μm, 10.8 μm, and 11.9 μm. EH36 and FH36 ship plate steel had the higher strength due to precipitation and grain boundary strengthening effect, while the E36 ship plate steel had the lower strength due to the recovery phenomenon in the normalizing process. EH36 and FH36 ship plate steel had higher impact toughness due to lower carbon (C) and silicon (Si) content and higher manganese (Mn) content than E36 ship plate steel. E36 ship plate steel had the best plasticity due to the two strong {110} and {111} texture components. The fracture toughness KJ0.2BL(30) values of E36 and EH36 and KJ0.2BL value of FH36 ship plate steel were, respectively, obtained at 387 MPa·m1/2, 464 MPa·m1/2 and 443 MPa·m1/2. EH36 and FH36 ship plate steel had higher KJ0.2BL(30) due to lower C and Si and higher Mn, niobium (Nb), vanadium (V), and aluminum (Al) content than the E36 ship plate steel. The fatigue crack growth rate of E36 ship plate steel was higher than that of EH36 and FH36 ship plate steel due to its higher carbon content and obviously smaller grain size. The analysis results and data may provide a necessary experimental basis for quantitatively establishing the relationship between fracture toughness, yield strength and impact toughness, as well as the relationship between fatigue crack growth rate and both strength and fracture toughness.

Fatigue Crack Growth Rate and Fracture Toughness of API5L X65 in Sweet Environments

2013 ◽  
Author(s):  
Michael A. Tognarelli ◽  
Ramgopal Thodla ◽  
Steven Shademan
Keyword(s):  
Fracture Toughness ◽  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Environmental Conditions ◽  
Initiation Toughness ◽  
Diffusible Hydrogen

Corrosion fatigue and fracture toughness in sour environments of APIX65 5L have typically been studied in relatively severe environments like NACE A and NACE B solutions. There are very limited data in sweet and mildly sour environments that are of interest in various applications. This paper presents fatigue crack growth frequency scans in a range of sweet and mildly sour environments as well as on different microstructures: Parent Pipe, Heat Affected Zone (HAZ) and Weld Center Line (WCL). The fatigue crack growth rate (FCGR) increased with decreasing frequency and reached a plateau value at low frequencies. FCGR in the sweet environments that were investigated did exhibit a frequency dependence (increasing with decreasing frequency) and had plateau FCGR in the range of 10–20× the in-air values. In the mildly sour environments that were investigated, FCGR was found to be about 25 to 30× higher than the in-air values. By comparison, in NACE A environments the FCGR is typically about 50× higher than the in-air values. The FCGRs of parent pipe and HAZ were found to be similar over a range of environments, whereas the WCL FCGR data were consistently lower by about a factor of 2×. The lower FCGR of the WCL is likely due to the lower concentration of diffusible hydrogen in the weld. FCGRs as a function of ΔK (stress integrity factor range) were measured on parent pipe at the plateau frequency. The measured Paris law curves were consistent with the frequency scan data. Rising displacement fracture toughness tests were performed in a range of sweet and sour environments to determine the R-curve behavior. Tests were performed in-situ at a slow K-rate of 0.05Nmm−3/2/s over a range of environmental conditions on parent pipe. The initiation toughness and the slope of the R-curve decreased sharply in the sour environments. The initiation toughness and slopes were largely independent of the notch location as well as environmental conditions. Typical values of initiation toughness were in the range of 90–110N/mm.

Fracture toughness and fatigue crack growth characteristics of nanotwinned copper

2011 ◽  
Vol 59 (6) ◽  
pp. 2437-2446 ◽  
Author(s):  
A. Singh ◽  
L. Tang ◽  
M. Dao ◽  
L. Lu ◽  
S. Suresh
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Characteristics
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