Evaluation of the influence of B and Nb microalloying on the microstructure and strength of 18% Ni maraging steels (C350) using hardness, spherical indentation and tensile tests

2021 ◽  
pp. 117071
Author(s):  
Sepideh Parvinian ◽  
Daniel E. Sievers ◽  
Hamid Garmestani ◽  
Surya R. Kalidindi
Keyword(s):  
Tensile Tests ◽  
Spherical Indentation ◽  
Maraging Steels ◽  
Nb Microalloying

The Spherical Indentation Approach for Fracture Toughness Evaluation: A Study Based on the Energy Release Rate

2018 ◽  
Author(s):  
Tairui Zhang ◽  
Weiqiang Wang ◽  
Aiju Li
Keyword(s):  
Fracture Toughness ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Damage Mechanism ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Spherical Indentation ◽  
Material Damage ◽  
Fracture Tests

In this study, we investigated the drawbacks of previous studies regarding the evaluation of fracture toughness from spherical indentation tests (SITs). This was achieved by an examination of the material damage mechanism during indentation tests, uniaxial tensile tests, and Mode I/II fracture tests. A new approach based on the energy release rate was proposed in this study to evaluate the fracture toughness of ductile metals. Scanning electron microscope (SEM) observations revealed that the mechanism for material damage during an indentation test was different with the material damage in uniaxial tensile tests and Mode I fracture tests, but similar to that in Mode II fracture tests. Thus, the energy release rate during SITs should be correlated with JIIC. Compared with previous studies, this new proposed method was more consistent with the actual damage mechanism and did not rely on the specific critical damage values. Experiments on SA508, SA533, 15CrMoR, and S30408 revealed that the maximum error from this energy release rate-based approach was no more than 13% when compared with their conventional counterparts (compact tension tests), and thus can meet the precision requirement of engineering applications.

Environmental Cracking of High Strength Maraging Steels: Part 2—Gaseous Fluoride Atmospheres

CORROSION ◽  
1981 ◽  
Vol 37 (2) ◽  
pp. 63-70
Author(s):  
D. H. Bradhurst ◽  
P. M. Heuer
Keyword(s):  
Hydrogen Fluoride ◽  
High Stress ◽  
High Strength ◽  
Uranium Hexafluoride ◽  
Tensile Tests ◽  
Maraging Steels ◽  
Partial Pressures ◽  
Mechanism Of Failure ◽  
Hydrogen Oxide ◽  
Gaseous Uranium

Abstract An investigation was made of the susceptibility to cracking of two commercial 350 grades of maraging steel. Tensile tests were carried out on samples of the steels at very slow strain rates, and the load at failure was used to assess the susceptibility of the steels to cracking in an environment of gaseous uranium hexafluoride and hydrogen fluoride at 70 C. Good resistance to cracking was observed in dry uranium hexafluoride gas but cracking occurred when hydrogen fluoride was present at partial pressures above about 1 kPa. The failure stress decreased with increasing pressure of hydrogen fluoride. Scanning electron microscopy revealed brittle fracture surfaces in all cases where failure occurred at low stress, while failures at high stress were usually ductile in appearance. In view of the susceptibility of these steels to hydrogen embrittlement, it is suggested that the mechanism of failure in the presence of HF was associated with reaction-produced hydrogen. Oxide coated samples prepared by air aging, did not have significantly better resistance to cracking than vacuum aged Samples in the UF6/HF environment.

scholarly journals Determination of the Plastic Strain by Spherical Indentation of Uniaxially Deformed Sheet Metals

2015 ◽  
Vol 651-653 ◽  
pp. 950-956 ◽  
Author(s):  
Mohamad Idriss ◽  
Olivier Bartier ◽  
Gérard Mauvoisin ◽  
Charbel Moussa ◽  
Eddie Gazo Hanna ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Accurate Determination ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Spherical Indentation ◽  
Instrumented Indentation ◽  
Forming Process ◽  
Hardening Law ◽  
Indentation Tests

This work consists of determining the plastic strain value undergone by a material during a forming process using the instrumented indentation technique (IIT). A deep drawing steel DC01 is characterized using tensile, shear and indentation tests. The plastic strain value undergone by this steel during uniaxial tensile tests is determined by indentation. The results show that, the identification from IIT doesn’t lead to an accurate value of the plastic strain if the assumption that the hardening law follows Hollomon law is used. By using a F.E. method, it is shown that using a Voce hardening law improves significantly the identification of the hardening law of a pre-deformed material. Using this type of hardening law coupled to a methodology based on the IIT leads to an accurate determination of the hardening law of a pre-deformed material. Consequently, this will allow determining the plastic strain value and the springback elastic strain value of a material after a mechanical forming operation.

Spherical indentation for determining the phase transition properties of shape memory alloys

2009 ◽  
Vol 24 (3) ◽  
pp. 1082-1086 ◽  
Author(s):  
Linmao Qian ◽  
Shuang Zhang ◽  
Dongyang Li ◽  
Zhongrong Zhou
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Tensile Tests ◽  
Deformation Analysis ◽  
Spherical Indentation ◽  
Indentation Method ◽  
Indentation Force ◽  
Depth Curves

A spherical indentation method was developed to characterize the phase transition behaviors of shape memory alloys (SMAs). Based on deformation analysis, the measured indentation force-depth curves of SMAs can be converted to their nominal stress-strain curves. The predicted elastic modulus and phase transition stress of SMAs from spherical indentation agree well with those directly measured from tensile tests. This approach should be especially useful for characterizing the phase transition properties of SMA materials of small size or thin films.

Inverse Characterization of Nonlinear Anisotropic Mechanical Properties of Engineered Cardiovascular Tissues Using a Spherical Indentation Test

2007 ◽  
Author(s):  
M. A. J. Cox ◽  
R. A. Boerboom ◽  
C. V. C. Bouten ◽  
N. J. B. Driessen ◽  
F. P. T. Baaijens
Keyword(s):  
Mechanical Properties ◽  
Soft Tissues ◽  
Indentation Test ◽  
Tensile Tests ◽  
Material Behavior ◽  
Uniaxial Tensile ◽  
Spherical Indentation ◽  
Mechanical Conditioning ◽  
Indentation Tests

Over the last few years, research interest in tissue engineering as an alternative for e.g. current treatment and replacement strategies for cardiovascular and heart valve diseaes has significantly increased. In vitro mechanical conditioning is an essential tool for engineering strong implantable tissues [1]. Detailed knowledge of the mechanical properties of the native tissue as well as the properties of the developing engineered constructs is vital for a better understanding and control of the mechanical conditioning process. The typical highly nonlinear and anisotropic behavior of soft tissues puts high demands on their mechanical characterization. Current standards in mechanical testing of soft tissues include (multiaxial) tensile testing and indentation tests. Uniaxial tensile tests do not provide sufficient information for characterizing the full anisotropic material behavior, while biaxial tensile tests are difficult to perform, and boundary effects limit the test region to a small central portion of the tissue. In addition, characterization of the local tissue properties from a tensile test is non-trivial. Indentation tests may be used to overcome some of these limitations. Indentation tests are easy to perform and when indenter size is small relative to the tissue dimensions, local characterization is possible. Therefore, we propose a spherical indentation test using finite deformations.

Characterisation of Elastoplastic Behaviour Using Spherical Indentation

2006 ◽  
Vol 514-516 ◽  
pp. 744-748
Author(s):  
António Castanhola Batista ◽  
José P. Marinheiro ◽  
Joao P. Nobre ◽  
A. Morão Dias
Keyword(s):  
Inverse Method ◽  
Indentation Test ◽  
Strain Curve ◽  
Tensile Tests ◽  
Spherical Indentation ◽  
Stress Strain Curve ◽  
Hardening Law ◽  
Behaviour Study ◽  
Behaviour Law ◽  
Good Agreement

An inverse method for the characterisation of the elastoplastic behaviour of materials has been studied. The method is based on spherical indentation test data and numerical analysis of the indentation process, enabling to find a characteristic stress-strain curve. This method will be appropriate for elastoplastic behaviour study, mainly on surface hardened materials, when the standard methods cannot be applied. In this work, the method was applied to annealed and quenched steels, with homogeneous properties over the cross section. The obtained results are in good agreement with those obtained from the standard tensile tests. However, if the material does not follow a linear hardening law, the elastoplastic characteristics determined by the inverse method will depend on the indentation depth. For these cases a method for the evaluation of the actual behaviour law has been improved.

Microstructure of resistance spot welding of maraging steels

1990 ◽  
Vol 48 (4) ◽  
pp. 900-901
Author(s):  
I. Neuman ◽  
S.F. Dirnfeld ◽  
I. Minkoff
Keyword(s):  
Maraging Steel ◽  
Spot Welding ◽  
Lath Martensite ◽  
Base Material ◽  
Aging Treatment ◽  
High Strength ◽  
Maraging Steels ◽  
Heat Treated ◽  
Current Cycle ◽  
Welding Processes

Experimental work on the spot welding of Maraging Steels revealed a surprisingly low level of strength - both in the as welded and in aged conditions. This appeared unusual since in the welding of these materials by other welding processes (TIG,MIG) the strength level is almost that of the base material. The maraging steel C250 investigated had the composition: 18wt%Ni, 8wt%Co, 5wt%Mo and additions of Al and Ti. It has a nominal tensile strength of 250 KSI. The heat treated structure of maraging steel is lath martensite the final high strength is reached by aging treatment at 485°C for 3-4 hours. During the aging process precipitation takes place of Ni3Mo and Ni3Ti and an ordered solid solution containing Co is formed.Three types of spot welding cycles were investigated: multi-pulse current cycle, bi-pulse cycle and single pulsle cycle. TIG welded samples were also tested for comparison.The microstructure investigations were carried out by SEM and EDS as well as by fractography. For multicycle spot welded maraging C250 (without aging), the dendrites start from the fusion line towards the nugget centre with an epitaxial growth region of various widths, as seen in Figure 1.

Sign in / Sign up

Export Citation Format

Share Document