Static and Cyclic Behavior of Welded DH36 Steel and Its Application at Low Temperatures

2021 ◽  
pp. 1-31
Author(s):  
Weidong Zhao ◽  
Guoqing Feng ◽  
Bernt J. Leira ◽  
Huilong Ren
Keyword(s):  
Mechanical Properties ◽  
Low Temperatures ◽  
Fatigue Tests ◽  
Cyclic Behavior ◽  
Brittle Transition ◽  
Ductile To Brittle Transition

Abstract The mechanical properties of welded DH36 steel at low temperatures are important to the safety of structures in Polar areas. The purpose of the study is to investigate the static and cyclic behavior of welded DH36 steel at low temperatures based on tensile and fatigue tests. The Ductile to Brittle transition and Fatigue Ductile to Brittle Transition of welded DH36 steel occurred at low temperatures. Finally, some relevant applications of the results within the context of polar engineering and design are discussed in the last part of the present study.

The Effects of Grain Size on the Flow and Fracture of Long-Range Ordered Alloys

1984 ◽  
Vol 39 ◽  
Author(s):  
Erland M. Schulson
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Refinement ◽  
Low Temperatures ◽  
Ferritic Steels ◽  
Brittle Transition ◽  
Ordered Alloys ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition ◽  
Grain Refinement Strengthening

Three points usually come to mind when considering the effects of grain size on the mechanical properties of polycrystals: strengthening at low temperatures through grain refinement, strengthening at high temperatures through grain coarsening, and lowering of the ductile to brittle transition temperature in materials such as ferritic steels and zinc through grain refinement. Ordered alloys, as we shall see, exhibit the same effects.

scholarly journals Investigation of the Mechanical Properties of St. Lawrence River Ice

1971 ◽  
Vol 8 (2) ◽  
pp. 163-169 ◽  
Author(s):  
L. W. Gold ◽  
A. S. Krausz
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Yield Stress ◽  
Power Law ◽  
River Ice ◽  
Stress Strain ◽  
Strain Behavior ◽  
Brittle Transition ◽  
Ductile To Brittle Transition ◽  
St Lawrence River

Observations are reported on the stress–strain behavior at −9.5 ± 0.5 °C of four types of ice obtained from the St. Lawrence River. The ice was subject to nominal rates of strain covering the range 2.1 × 10−5 min−1 to 5.8 × 10−2 min−1. A ductile-to-brittle transition was observed for strain rate of about 10−2 min−1. In the ductile range the four types had an upper yield stress that increased with strain rate according to a power law.

scholarly journals Coupling between Welding Conditions and Thermal Cycling for Identification of the Mechanical Heterogeneity of a Weld Joint

2018 ◽  
Vol 62 (3) ◽  
pp. 226-232
Author(s):  
Fatima Zohra Messabih ◽  
Benattou Bouchouicha
Keyword(s):  
Weld Joint ◽  
Low Temperatures ◽  
Thermal Cycle ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Transition Curve ◽  
Mechanical Heterogeneity ◽  
Break Junctions ◽  
Brittle Transition ◽  
Strength Tests

The analyses device safety subject to pressure is based on the prediction at break junctions used for the design of this type of devices. The harmfulness analysis of existing defects on these devices makes indispensable the study of the rupture in these components. Various characterization tests (tensile tests, fatigue tests and tensile strength tests) were carried out at room and low temperatures on plates welded end to end and for the different directions of sampling.An estimate of the toughness in the three areas of a weld joint was made by passing from resilience to toughness in the ductile-brittle transition zone of materials. The temperature range of the tests was to provide measurements of the toughness the lower bearing to the beginning of the transition curve. The purpose of this work is to study the state both mechanical and microstructural aspects of the welded junction. The diagnoses used made it possible to deduce that the small thickness of the HAZ, makes the machining of the specimen difficult. Thereby, a mechanical simulation of the HAZ by registration of the thermal cycle that this area undergoes was necessary to be able to reproduce it and compare it with the actual HAZ.

Ternary MoSi2 Compounds for High Temperature Structural Applications

1993 ◽  
Vol 322 ◽  
Author(s):  
S. Chin ◽  
D. L. Anton ◽  
A. F. Giamei
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Isothermal Oxidation ◽  
Phase Boundaries ◽  
Brittle Transition ◽  
Flexural Testing ◽  
Structural Applications ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition ◽  
Oxidation Testing

AbstractThe microstructure and phase composition of MoSi2 modified with Al, B, Ge, Hf, Nb, and Re have been investigated. B and Hf substitutions for Si and Mo, respectively, exhibited very low solubilities in MoSi2. Al and Nb substitutions for Si and Mo, respectively, changed the crystal structure from tetragonal C11b to hexagonal C40. Phase boundaries and solubility limits were determined for Al and Nb substitutions. Ge and Re substitutions for Si and Mo, respectively, exhibited complete solubility and maintained the tetragonal Cllb crystal structure. The mechanical properties evaluation as determined by four-point flexural testing indicate a ductile-to-brittle transition temperature (DBTT) of 1250-1350°C for all of the modifications evaluated. Isothermal oxidation testing at 1400°C indicates no significant debit in oxidation resistance of MoSi2 that can be attributed to alloying, however, alloys containing higher concentrations of the ternary elements may exhibit reduced oxidation resistances.

Mechanical Properties of Flip-Chip Solder Joints Effected by Electromigration

2011 ◽  
Vol 189-193 ◽  
pp. 1009-1013 ◽  
Author(s):  
Yu Dong Lu ◽  
Yun Fei En ◽  
Ming Wan ◽  
Xiao Qi He ◽  
Xin Wang
Keyword(s):  
Mechanical Properties ◽  
Solder Joint ◽  
High Speed ◽  
Flip Chip ◽  
Solder Joints ◽  
Interfacial Structure ◽  
Polarity Effect ◽  
Brittle Transition ◽  
Cause Of Failure ◽  
Ductile To Brittle Transition

A frequent cause of failure of portable and hand-held devices is an accidental drop to the ground. The effect of electromigration on the mechanical properties of solder joints was discussed in this paper. Without current stressing, the samples were broken in the bulk of solder or at the interface of Al interconnect and solder. If the Al-solder interfacial mechanical strength was improved by changed the interfacial structure or optimized the jointing process, the flip chip devices would show the lonely ductile fracture in the bulk of solder. After electromigration the samples were broken abruptly at the interface near the chip side while the bulk of the solder joints maintained the original shape. Due to the interfacial reaction and the polarity effect of electromigration on the interfaces, a ductile solder joint can become a brittle solder joint. The ductile-to-brittle transition is very sensitive to a high speed shear stress applied to the joints. Because solder alloys are ductile by nature, it is of interest to understand how electromigration can influence the mechanical properties of solder joints’ interfaces and change their ductile nature. Owing to the polarity effect of electromigration, vacancies will accumulate to form voids at the cathode interface of solder joints. Besides, much more intermetallic compound formation at the joint interfaces also caused the ductile-to-brittle transition. Thus the interfaces become more and more brittle with time due to IMC formation or vacancy accumulation from electromigration.

scholarly journals Mechanical Properties and Impact Toughness of Molybdenum Alloyed Ductile Iron

2020 ◽  
Author(s):  
D. Franzen ◽  
B. Pustal ◽  
A. Bührig-Polaczek
Keyword(s):  
Mechanical Properties ◽  
Transition Temperature ◽  
Ductile Iron ◽  
Calculated Data ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Brittle Transition ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition ◽  
High Silicon

Abstract Grades of high silicon ductile iron offer excellent combinations of static strength and ductility as well as good machinability due to their fully ferritic, solution strengthened matrix. As a result of elevated silicon contents, however, the ductile-to-brittle transition temperature in the Charpy impact test is significantly increased. Thus, minimum required Charpy impact energies cannot be met for many applications by using high silicon ductile iron. Therefore, alloys with lower strength and higher toughness properties are commonly used for many technical applications. The enormous lightweight construction potential of high silicon ductile iron can therefore not be fully exploited. The present investigation pursues the metallurgical approach of partially substituting silicon with molybdenum as an alternative strengthening element in order to improve the toughness properties while maintaining similar static mechanical properties. Molybdenum serves as a carbide-stabilising element in ductile iron, while simultaneously promoting ferrite formation and is therefore regarded to be suitable alloying element. In Charpy impact tests, the ductile-to-brittle transition temperature could be reduced by about 55 °C by reducing the silicon content to 2.95 wt% and adding 0.21 wt% molybdenum compared to a high silicon alloy. Additionally, it was possible to mathematically describe the transition behaviour of the studied alloys using nonlinear regression functions and to achieve a sufficient correlation of empirically determined and calculated data. This present metallurgical concept offers a promising metallurgical tool for further improving the toughness properties of alloyed ductile iron.

Microstructures and Mechanical Properties of Directionally Solidified Intermetallic Composites

2007 ◽  
Vol 539-543 ◽  
pp. 1495-1500 ◽  
Author(s):  
H. Bei ◽  
E.P. George
Keyword(s):  
Mechanical Properties ◽  
Growth Rate ◽  
Tensile Tests ◽  
Square Root ◽  
Directionally Solidified ◽  
Brittle Transition ◽  
Fiber Size ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition ◽  
Nial Matrix

This paper reviews two kinds of well-aligned fibrous microstructures produced by directional solidification of NiAl-Mo and Fe-Fe2Ta eutectics. In both these composites, fiber size and spacing decrese inversely as the square root of the growth rate. Tensile tests as a function of temperature showed that the NiAl-Mo composite has a higher yield strength and lower ductile-to-brittle transition temperature than the NiAl matrix. For the Fe-Fe2Ta composite, yield strengths in excess of 700 MPa were obtained at temperatures to 600°C, with elongations to fracture of ~3% which remained roughly constant at temperatures to 950°C.

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