Creating Tensile Fractures in Colorado Shale Using an Unconfined Fast Heating Test

AbstractTi75Ta25 high-temperature shape memory alloys exhibit a number of features which make it difficult to use them as spring actuators. These include the high melting point of Ta (close to 3000 °C), the affinity of Ti to oxygen which leads to the formation of brittle α-case layers and the tendency to precipitate the ω-phase, which suppresses the martensitic transformation. The present work represents a case study which shows how one can overcome these issues and manufacture high quality Ti75Ta25 tensile spring actuators. The work focusses on processing (arc melting, arc welding, wire drawing, surface treatments and actuator spring geometry setting) and on cyclic actuator testing. It is shown how one can minimize the detrimental effect of ω-phase formation and ensure stable high-temperature actuation by fast heating and cooling and by intermediate rejuvenation anneals. The results are discussed on the basis of fundamental Ti–Ta metallurgy and in the light of Ni–Ti spring actuator performance.

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Improving formability and retaining dislocation hardening of heavily cold-worked Al alloy by fast heating and fast deformation

Materials Science and Engineering A ◽

10.1016/j.msea.2021.141455 ◽

2021 ◽

pp. 141455

Author(s):

Guohui Li ◽

Chunhui Liu ◽

Peipei Ma ◽

Jianshi Yang ◽

Zhuangzhuang Feng

Keyword(s):

Al Alloy ◽

Fast Heating ◽

Dislocation Hardening ◽

Cold Worked

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A Compact Review of Laser Welding Technologies for Amorphous Alloys

Metals ◽

10.3390/met10121690 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1690

Author(s):

Jian Qiao ◽

Peng Yu ◽

Yanxiong Wu ◽

Taixi Chen ◽

Yixin Du ◽

...

Keyword(s):

Amorphous Alloy ◽

Laser Welding ◽

Amorphous Alloys ◽

High Energy ◽

Industrial Applications ◽

High Energy Density ◽

Current Status ◽

Future Research ◽

Technological Parameters ◽

Fast Heating

Amorphous alloys have emerged as important materials for precision machinery, energy conversion, information processing, and aerospace components. This is due to their unique structure and excellent properties, including superior strength, high elasticity, and excellent corrosion resistance, which have attracted the attention of many researchers. However, the size of the amorphous alloy components remains limited, which affects industrial applications. Significant developments in connection with this technology are urgently needed. Laser welding represents an efficient welding method that uses a laser beam with high energy-density for heating. Laser welding has gradually become a research hotspot as a joining method for amorphous alloys due to its fast heating and cooling rates. In this compact review, the current status of research into amorphous-alloy laser welding technology is discussed, the influence of technological parameters and other welding conditions on welding quality is analyzed, and an outlook on future research and development is provided. This paper can serve as a useful reference for both fundamental research and engineering applications in this field.

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Investigation on the mechanical properties of press-hardened boron steel sheets using the conductive heating technique

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420720926532 ◽

2020 ◽

Vol 234 (8) ◽

pp. 1084-1098

Author(s):

O Kocar ◽

H Livatyalı

Keyword(s):

Mechanical Properties ◽

High Speed ◽

Boron Steel ◽

Fast Heating ◽

Heating Method ◽

Conductive Heating ◽

Press Hardening ◽

High Speed Impact ◽

Significant Difference ◽

Structural Parts

An aluminized 22MnB5 (Boron) steel sheet, used for structural parts in the automotive industry, was subjected to press-hardening followed by austenitizing, both in a conventional furnace and via the conductive (electric resistance) heating method, an innovative technique based on the Joule’s principle for fast heating of the sheet metal. Conductive heating presents a number of advantages over the in-furnace heating method. These include a more efficient use of energy, as well as the requirement of less time and space for heating, thus lowering costs. After press-hardening was performed using both methods, the microstructural and mechanical characterizations of both specimens were examined for optical microscopy, hardness, tensile strength, and high-speed impact tests. The results showed that the press-hardening process transformed the ferritic–pearlitic microstructure in the as-received state into martensite after die quenching and caused a substantial increase in hardness and strength at the expense of ductility and impact toughness. On the other hand, no significant difference was observed in either the microstructure or mechanical properties with respect to the heating method used. The results obtained in the present investigation concur with the findings of current literature.

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