scholarly journals Assessment of microstructure stability and mechanical properties of X10CrWMoVNb9-2 (P92) steel after long-term thermal ageing for high-temperature applications

2016 ◽  
Vol 54 (01) ◽  
pp. 61-70 ◽  
Author(s):  
A. Zieliński ◽  
G. Golański ◽  
M. Sroka
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Thermal Ageing ◽  
P92 Steel ◽  
Microstructure Stability ◽  
Temperature Applications

scholarly journals Study on microstructure and mechanical properties of P92 steel after high-temperature long-term aging at 650°C

2020 ◽  
Vol 39 (1) ◽  
pp. 545-555
Author(s):  
Peng Duan ◽  
Zongde Liu ◽  
Bin Li ◽  
Jiayao Li ◽  
Xiangqian Tao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Optical Microscope ◽  
Strength Properties ◽  
Continuous Precipitation ◽  
P92 Steel ◽  
Aging Period ◽  
High Temperature Mechanical Properties ◽  
Early Aging

AbstractA series of long-term high-temperature aging tests of ASME A335-P92 steel from 1,000 to 29,000 h at 650°C were carried out. The microstructure evolution of as-received and aging specimens at different stages was investigated using optical microscope observations, scanning electron microscope examinations, and TEM investigations. The static mechanical strength properties (yield strength/ultimate tensile strength) at room and 600°C test temperatures and the plastic performance (elongation/reduction in area) were also analyzed. The experimental results show that the Laves phase can be precipitated rapidly in the early aging period. After a certain aging period, the continuous precipitation of M23C6 and the relatively high coarsening rate of Laves resulted in a rapid decrease of room and high-temperature mechanical properties in the early aging period. However afterwards for the long aging time, a slow decline in tendency of mechanical properties was presented.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

Polyimide Copolymers Containing Various Levels Of The 6F Moiety For High Temperature And Microelectronic Applications

1991 ◽  
Vol 227 ◽  
Author(s):  
M. Haider ◽  
E. Chenevey ◽  
R. H. Vora ◽  
W. Cooper ◽  
M. Glick ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Electrical Properties ◽  
Oxidative Stability ◽  
Trifluoromethyl Group ◽  
Thermal And Mechanical Properties

ABSTRACTTrifluoromethyl group-containing polyimides not only show extraordinary electrical properties, but they also exhibit excellent long-term thermo-oxidative stability. Among the most thermomechanically stable structural polyimides are those from 6F dianhydride (6FDA) and 6F diamines. The effects of substituting non-fluorine containing monomers such as BTDA, mPDA and 4,4′-DADPS for the hexafluoroisopropylidene monomers on the dielectric, thermo-oxidative, thermal and mechanical properties of the copolymers were studied.

Initial properties and ageing behaviour of pineapple leaf and palm fibre as reinforcement for polypropylene

2016 ◽  
Vol 30 (2) ◽  
pp. 174-195 ◽  
Author(s):  
Rungsima Chollakup ◽  
Haroutioun Askanian ◽  
Florence Delor-Jestin
Keyword(s):  
Mechanical Properties ◽  
Cost Effective ◽  
Tensile Tests ◽  
Natural Fibre ◽  
Thermal Ageing ◽  
Second Step ◽  
Scanning Calorimetry ◽  
Ultraviolet Exposure ◽  
Palm Fibre

In the furniture, automotive and contruction industries, there is increased demand for cost-effective and lightweight biocomposites. The objective of this work was to develop new natural fibre-based composites with specific properties. Palm and pineapple leaf fibres were chosen in association with polypropylene (PP). The first step was to investigate the effect of these natural fibres as reinforcement for PP. The evolution of chemical structure and crystallinity was proposed with infrared spectroscopy measurements and differential scanning calorimetry thermograms, respectively. The assessments of mechanical properties with tensile tests and melt viscoelastic behaviour were also investigated. The study enabled to distinguish the influence of fibre content. The second step in our work was to assess the composite durability after ultraviolet exposure or thermal ageing. The oxidation level was calculated. The long-term evolution of thermal and mechanical properties was also proposed. As a result, the PP/pineapple leaf composite revealed a promising biocomposite.

Research on Barite Concrete Mixed with Fly Ash

2013 ◽  
Vol 275-277 ◽  
pp. 2107-2111
Author(s):  
Qiu Lin Zou ◽  
Jun Li ◽  
Zhen Yu Lai
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Compressive Strength ◽  
High Temperature ◽  
Fly Ash ◽  
Apparent Density ◽  
Cycle Times ◽  
Residual Compressive Strength ◽  
Temperature Performance

Barite concrete with density grade of 3 and strength grade of C30 was prepared by mixing with different fineness of fly ash. The workability, mechanical properties and long-term high temperature performance of the prepared barite concrete were researched. Results show that the workability of barite concrete is improved by mixing with fly ash, and no segregation of mixture has been observed. The apparent density and 3d, 28d compressive strength of barite concrete are decreased obviously after mixing with fly ash. But with the increasing of the fineness of fly ash, the apparent density and 3d, 28d compressive strength of barite concrete have a slight increase. High temperature residual compressive strength is decreased with the increasing of temperature. The cycle times of heat treatment at 400°C only has a little effect on residual compressive strength of barite concrete.

Mitigation of High Temperature Environments on Electrical Disconnects

2018 ◽  
Vol 2018 (HiTEC) ◽  
pp. 000148-000153
Author(s):  
Kenneth P. Dowhower
Keyword(s):  
High Temperature ◽  
Electrical Properties ◽  
Stress Relaxation ◽  
Surface Treatment ◽  
Material Properties ◽  
Mechanical Stability ◽  
Contact Interface ◽  
Insulating Materials ◽  
Temperature Applications

Abstract The electrical interconnect is an essential component of most electrical system configurations. The ability of the interconnect interface to reliably transmit power and / or data throughout the system is critical to its overall performance. Degradation of the mechanical or electrical properties of the interface can reduce the system performance or in severe cases, make it inoperable. There are several factors which can inhibit the performance of the interconnect, one of most severe is long term exposure to elevated temperatures. This effect can also be accelerated when combined with other severe environmental conditions such as high vibration and physical shock, which are often found in down hole oil and gas well drilling applications. This type of exposure can significantly degrade the essential properties of a reliable electrical interface such as contact resistance, mechanical stability, and electrical isolation. This paper will present options for design features and material properties that can be incorporated into an interconnect design that will mitigate these adverse effects. Specifically, this paper addresses the material properties of the contact interface and its surface treatment, the mechanical and electrical properties of the insulating material, the robustness of the mating features and the contact retention system. Two key features of the contact interface that are discussed are the stability of its electrical resistance and the robustness of its mechanical retention. Long term exposure to high temperatures typically induces stress relaxation in the compliant members of the contact interface that are required to produce a stable, low resistance interface, while allowing for a high level of mate / unmate durability. Stress relaxation can also reduce the mechanical stability of the contact interface where metal or plastic retention features are utilized. In the case of retention through epoxy bonding, imparting thermal stress at the bonding surface can result in loss of adhesion and / or retention. The surface treatment of the contact interface has also been shown to be a contributing factor in its electrical stability in high temperature applications. Typically, the interface is plated with a hard gold over nickel finish, which provides a noble interface that is corrosion resistant, but with the hardness required to withstand many mate / unmate cycles. A small percentage of nickel or cobalt are typically alloyed with the gold to produce the required hardness. In most applications, it has minimal impact on the overall resistance of the contact interface. In high temperature applications, however, it can tend to diffuse through the gold to the contact interface. Since these materials have a higher resistivity, they can negatively affect the resistance of the interface. The impact of this effect is reviewed in this paper. Finally, results of the evaluations on high temperature insulating materials and bonding epoxies are presented in this paper. The mechanical and dielectric stability of the insulating materials and the adhesion properties of the epoxy used for contact retention were the primary concerns for their evaluation. The verification tests that included at temperature exposure were conducted at +260°C to simulate extreme use cases for most down hole applications.

Flip-Chip Ball Grid Array Lead-Free Solder Joint Under Reliability Test

2005 ◽  
Vol 127 (4) ◽  
pp. 446-451 ◽  
Author(s):  
Ming-Hwa R. Jen ◽  
Lee-Cheng Liu ◽  
Jenq-Dah Wu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Service Time ◽  
Flip Chip ◽  
Failure Modes ◽  
Mechanical Responses ◽  
Operational Life ◽  
Different Temperatures ◽  
Free Solder

The work is aimed to investigate the mechanical responses of bare dies of the combination of pure tin∕Al–NiV–Cu Under bump metallization (UBM) and packages of pure tin∕Al–NiV–Cu UBM/substrate of standard thickness of aurum. The mechanical properties under multiple reflow and long term high temperature storage test (HTST) tests at different temperatures and the operational life were obtained. A scanning electron microscope was used to observe the growth of IMC and the failure modes in order to realize their reaction and connection. From the empirical results of bare dies, the delamination between IMC and die was observed due to the tests at 260 °C multiple reflow. However, their mechanical properties were not affected. Nevertheless, the bump shear strength of bare dies were decreased by HTST tests. In package, all the results of mechanical properties by multiple reflow test and HTST test were significantly lowered. It was shown that the adhesion between bump and die reduced obviously as tests going on. As for high temperature operational life test in the conditions of 150 °C and 320 mA (5040A∕cm2), the average stable service time of the package was 892 h, and the average ultimate service time of the package was 1053 h.

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