scholarly journals Semiconducting polymer blends that exhibit stable charge transport at high temperatures

Science ◽  
2018 ◽  
Vol 362 (6419) ◽  
pp. 1131-1134 ◽  
Author(s):  
Aristide Gumyusenge ◽  
Dung T. Tran ◽  
Xuyi Luo ◽  
Gregory M. Pitch ◽  
Yan Zhao ◽  
...  
Keyword(s):  
High Temperature ◽  
Polymer Blends ◽  
Charge Transport ◽  
Organic Semiconductors ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Hole Mobility ◽  
General Strategy ◽  
Semiconducting Polymer ◽  
High Temperature Operation

Although high-temperature operation (i.e., beyond 150°C) is of great interest for many electronics applications, achieving stable carrier mobilities for organic semiconductors at elevated temperatures is fundamentally challenging. We report a general strategy to make thermally stable high-temperature semiconducting polymer blends, composed of interpenetrating semicrystalline conjugated polymers and high glass-transition temperature insulating matrices. When properly engineered, such polymer blends display a temperature-insensitive charge transport behavior with hole mobility exceeding 2.0 cm2/V·s across a wide temperature range from room temperature up to 220°C in thin-film transistors.

FANSTEEL 85 METAL

Alloy Digest ◽  
1981 ◽  
Vol 30 (6) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Creep Strength ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
Heat Treating ◽  
Good Combination ◽  
Bend Strength ◽  
Temperature Performance

Abstract FANSTEEL 85 METAL is a columbium-base alloy characterized by good fabricability at room temperature, good weldability and a good combination of creep strength and oxidation resistance at elevated temperatures. Its applications include missile and rocket components and many other high-temperature parts. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and bend strength as well as creep. It also includes information on low and high temperature performance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Cb-7. Producer or source: Fansteel Metallurgical Corporation. Originally published December 1963, revised June 1981.

Martensite decomposition during post-heat treatments and the aging response of near-α Ti–6Al–2Sn–4Zr–2Mo (Ti-6242) titanium alloy processed by selective laser melting (SLM)

2021 ◽  
pp. 2050018
Author(s):  
Haiyang Fan ◽  
Yahui Liu ◽  
Shoufeng Yang
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Titanium Alloys ◽  
Selective Laser Melting ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Aging Treatment ◽  
Water Quenching ◽  
Laser Melting ◽  
Aging Response

Ti–6Al–2Sn–4Zr–2Mo (Ti-6242), a near-[Formula: see text] titanium alloy explicitly designed for high-temperature applications, consists of a martensitic structure after selective laser melting (SLM). However, martensite is thermally unstable and thus adverse to the long-term service at high temperatures. Hence, understanding martensite decomposition is a high priority for seeking post-heat treatment for SLMed Ti-6242. Besides, compared to the room-temperature titanium alloys like Ti–6Al–4V, aging treatment is indispensable to high-temperature near-[Formula: see text] titanium alloys so that their microstructures and mechanical properties are pre-stabilized before working at elevated temperatures. Therefore, the aging response of the material is another concern of this study. To elaborate the two concerns, SLMed Ti-6242 was first isothermally annealed at 650[Formula: see text]C and then water-quenched to room temperature, followed by standard aging at 595[Formula: see text]C. The microstructure analysis revealed a temperature-dependent martensite decomposition, which proceeded sluggishly at [Formula: see text]C despite a long duration but rapidly transformed into lamellar [Formula: see text] above the martensite transition zone (770[Formula: see text]C). As heating to [Formula: see text]C), it produced a coarse microstructure containing new martensites formed in water quenching. The subsequent mechanical testing indicated that SLM-built Ti-6242 is excellent in terms of both room- and high-temperature tensile properties, with around 1400 MPa (UTS)[Formula: see text]5% elongation and 1150 MPa (UTS)[Formula: see text]10% elongation, respectively. However, the combination of water quenching and aging embrittled the as-built material severely.

scholarly journals Comparison of Mechanical and Microstructural Properties of as-Cast Al-Cu-Mg-Ag Alloys: Room Temperature vs. High Temperature

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1330
Author(s):  
Muhammad Farzik Ijaz ◽  
Mahmoud S. Soliman ◽  
Ahmed S. Alasmari ◽  
Adel T. Abbas ◽  
Faraz Hussain Hashmi
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Mechanical Testing ◽  
Tensile Testing ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Microstructural Properties ◽  
Testing Environments ◽  
Mechanical And Microstructural Properties ◽  
Mg Content

Unfolding the structure–property linkages between the mechanical performance and microstructural characteristics could be an attractive pathway to develop new single- and polycrystalline Al-based alloys to achieve ambitious high strength and fuel economy goals. A lot of polycrystalline as-cast Al-Cu-Mg-Ag alloy systems fabricated by conventional casting techniques have been reported to date. However, no one has reported a comparison of mechanical and microstructural properties that simultaneously incorporates the effects of both alloy chemistry and mechanical testing environments for the as-cast Al-Cu-Mg-Ag alloy systems. This preliminary prospective paper presents the examined experimental results of two alloys (denoted Alloy 1 and Alloy 2), with constant Cu content of ~3 wt.%, Cu/Mg ratios of 12.60 and 6.30, and a constant Ag of 0.65 wt.%, and correlates the synergistic comparison of mechanical properties at room and elevated temperatures. According to experimental results, the effect of the precipitation state and the mechanical properties showed strong dependence on the composition and testing environments for peak-aged, heat-treated specimens. In the room-temperature mechanical testing scenario, the higher Cu/Mg ratio alloy with Mg content of 0.23 wt.% (Alloy 1) possessed higher ultimate tensile strength when compared to the low Cu/Mg ratio with Mg content of 0.47 wt.% (Alloy 2). From phase constitution analysis, it is inferred that the increase in strength for Alloy 1 under room-temperature tensile testing is mainly ascribable to the small grain size and fine and uniform distribution of θ precipitates, which provided a barrier to slip by deaccelerating the dislocation movement in the room-temperature environment. Meanwhile, Alloy 2 showed significantly less degradation of mechanical strength under high-temperature tensile testing. Indeed, in most cases, low Cu/Mg ratios had a strong influence on the copious precipitation of thermally stable omega phase, which is known to be a major strengthening phase at elevated temperatures in the Al-Cu-Mg-Ag alloying system. Consequently, it is rationally suggested that in the high-temperature testing scenario, the improvement in mechanical and/or thermal stability in the case of the Alloy 2 specimen was mainly due to its compositional design.

Tensile Behaviour of Al-Si Alloy and Al-Si/Graphite Composites at Elevated Temperatures

2012 ◽  
Vol 710 ◽  
pp. 457-462 ◽  
Author(s):  
G. Rajaram ◽  
S. Kumaran ◽  
T Srinivas Rao
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Matrix Alloy ◽  
Tensile Behaviour ◽  
Fracture Mechanisms ◽  
Strain Hardening Exponent ◽  
Transition Elements ◽  
Softening Effect ◽  
Graphite Composite

The high temperature tensile behaviour of Al-Si alloy and two of its composite systems with graphite as major reinforcement were investigated. The composites were developed by the stir casting method, wherein a mixture of graphite (3 wt %) and Cu / Ni (2 wt% each) were added into the molten Al-Si alloy to fabricate two systems such as Al-Si-Cu/graphite composite and Al-Si-Ni/graphite composite. The properties of composites were better than that of the matrix alloy. Tensile behaviour of alloy and composites were studied at different temperatures from room temperature to 300°C. It is found that the tensile strength of the alloy and composites were decreasing with increase in temperature. The transition elements (Cu / Ni) have played the key role in improving the ultimate tensile and yield strength of the composites over the alloy. The flow stress of the composite is more than that of the alloy. The strain hardening exponent value continuously drops with the increase of tensile temperature due to the thermal softening effect. The % elongation of the alloy is more than that of the composites. Fracture surfaces of the samples are analyzed by scanning electron microscope to understand the fracture mechanisms. Fractography reveals that the fracture behaviour of the alloy changes from cleavage mode at room temperature to complete ductile mode at high temperature.

1700V, 5.5mOhm-cm2 4H-SiC DMOSFET with Stable 225°C Operation

2014 ◽  
Vol 778-780 ◽  
pp. 903-906 ◽  
Author(s):  
Kevin Matocha ◽  
Kiran Chatty ◽  
Sujit Banerjee ◽  
Larry B. Rowland
Keyword(s):  
High Temperature ◽  
Temperature Stress ◽  
High Temperatures ◽  
Threshold Voltage ◽  
Room Temperature ◽  
Gate Bias ◽  
Threshold Voltage Shift ◽  
Device Reliability ◽  
Bias Temperature Stress ◽  
High Temperature Operation

We report a 1700V, 5.5mΩ-cm24H-SiC DMOSFET capable of 225°C operation. The specific on-resistance of the DMOSFET designed for 1200V applications is 8.8mΩ-cm2at 225°C, an increase of only 60% compared to the room temperature value. The low specific on-resistance at high temperatures enables a smaller die size for high temperature operation. Under a negative gate bias temperature stress (BTS) at VGS=-15 V at 225°C for 20 minutes, the devices show a threshold voltage shift of ΔVTH=-0.25 V demonstrating one of the key device reliability requirements for high temperature operation.

Mechanical Behavior of 2D C/SiC Composites at Elevated Temperatures under Uniaxial Compression

2011 ◽  
Vol 462-463 ◽  
pp. 1-6 ◽  
Author(s):  
Tao Suo ◽  
Yu Long Li ◽  
Ming Shuang Liu
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Carbon Fiber ◽  
Mechanical Behavior ◽  
Uniaxial Compression ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Carbon Matrix ◽  
Structural Applications ◽  
Sic Composites

As Carbon-fiber-reinforced SiC-matrix (C/SiC) composites are widely used in high-temperature structural applications, its mechanical behavior at high temperature is important for the reliability of structures. In this paper, mechanical behavior of a kind of 2D C/SiC composite was investigated at temperatures ranging from room temperature (20C) to 600C under quasi-static and dynamic uniaxial compression. The results show the composite has excellent high temperature mechanical properties at the tested temperature range. Catastrophic brittle failure is not observed for the specimens tested at different strain rates. The compressive strength of the composite deceases only 10% at 600C if compared with that at room temperature. It is proposed that the decrease of compressive strength of the 2D C/SiC composite at high temperature is influenced mainly by release of thermal residual stresses in the reinforced carbon fiber and silicon carbon matrix and oxidation of the composite in high temperature atmosphere.

Influence of High-Temperature Bias Stress on Room-Temperature VT Drift Measurements in SiC Power MOSFETs

2019 ◽  
Vol 963 ◽  
pp. 757-762
Author(s):  
Daniel B. Habersat ◽  
Aivars Lelis ◽  
Ronald Green
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
State Of The Art ◽  
Charge Trapping ◽  
High Temperature Stress ◽  
Test Method ◽  
Power Mosfets ◽  
Temperature Bias ◽  
Bias Stress

Our results reinforce the notion of the need for an improved high-temperature gate bias (HTGB) test method — one which discourages the use of slow (greater than ~1 ms) threshold-voltage (VT) measurements at elevated temperatures and includes biased cool-down if room temperature measurements are performed, to ensure that any ephemeral effects during the high-temperature stress are observed. The paper presents a series of results on both state-of-the-art commercially-available devices as well as older vintage devices that exhibit enhanced charge-trapping effects. Although modern devices appear to be robust, it is important to ensure that any new devices released commercially, especially by new vendors, are properly evaluated for VT stability.

Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends

2010 ◽  
Vol 22 (11) ◽  
pp. 3543-3548 ◽  
Author(s):  
Nichole C. Cates ◽  
Roman Gysel ◽  
Jeremy E. P. Dahl ◽  
Alan Sellinger ◽  
Michael D. McGehee
Keyword(s):  
Polymer Blends ◽  
Hole Mobility ◽  
Semiconducting Polymer

Normally-off GaN MOSFETs on Silicon Substrates with High-temperature Operation

2009 ◽  
Vol 1202 ◽  
Author(s):  
Hiroshi Kambayashi ◽  
Yuki Niiyama ◽  
Takehiko Nomura ◽  
Masayuki Iwami ◽  
yoshihiro Satoh ◽  
...  
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Silicon Substrates ◽  
Enhancement Mode ◽  
Threshold Voltages ◽  
Source Voltage ◽  
Gan Hfet ◽  
Output Characteristics ◽  
High Temperature Operation ◽  
State Resistance

AbstractWe have demonstrated enhancement-mode n-channel gallium nitride (GaN) MOSFETs on Si (111) substrates with high-temperature operation up to 300 °C. The GaN MOSFETs have good normally-off operation with the threshold voltages of +2.7 V. The MOSFET exhibits good output characteristics from room temperature to 300 °C. The leakage current at 300°C is less than 100 pA/mm at the drain-to-source voltage of 0.1 V. The on-state resistance of MOSFET at 300°C is about 1.5 times as high as that at room temperature. These results indicate that GaN MOSFET is suitable for high-temperature operation compared with AlGaN/GaN HFET.

An Ultrasonic Non-Contact Handling Device from Quartz Glass for Middle and High Temperature Applications

2014 ◽  
Vol 1018 ◽  
pp. 31-38
Author(s):  
Edgars Locmelis
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Manufacturing Processes ◽  
Mechanical Contact ◽  
High Temperature Region ◽  
Handling Device ◽  
Design And Manufacturing ◽  
Different Temperatures ◽  
Small Change

Ultrasonic non-contact handling is used to manipulate surface sensitive and fragile workpieces, e.g. wafers and glass plates, without mechanical contact. While the technology is available forapplications at room temperature, some of the manufacturing processes of products mentioned aboverequire handling at elevated temperatures. To enable this technology for handling in thermal processesan ultrasonic system for increased working temperatures is required. In order to adapt the ultrasonicsystem to the limited working temperature of the actuator, the handling system has to be operated attwo different temperatures. Due to the small change of the Young's modulus over temperature, quartzglass was chosen as material for the components in the high temperature region. The paper presentsthe design and manufacturing of a novel ultrasonic system operated at 790 °C while the actuator iskept at room temperature.

Sign in / Sign up

Export Citation Format

Share Document