Aging effects on hardness and dynamic compressive behavior of Ti-55Ni (at.%) alloy

作者：Adharapurapu Raghavendra R; Jiang Fengchun; Vecchio Kenneth S^*

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2010, 527(7-8): 1665-1676.

DOI：10.1016/j.msea.2009.10.069

• Ni-rich Ni-Ti
• Aging
• Precipitation
• Hardness
• High-strain rate

Materials for impact applications require a unique combination of high hardness, high dynamic compressive strength, and reasonable toughness (i.e., suitable ductility). This paper presents the aging effects on the microstructural evolution, hardness, and compressive high-strain rate behavior of Ni-rich Ti-55Ni (at.%) alloy. Aging heat-treatments of Ti-55Ni between 400 degrees C and 1000 degrees C led to the following precipitation sequence: Ti(3)Ni(4) -> T(2)Ni(3) -> TiNi(3). Among these, Ti(3)Ni(4) and T(2)Ni(3) were found to be metastable phases since they transformed to TiNi(3) phase during longer aging times or higher aging temperatures. Initial investigations were focused on precipitation studies to obtain a time-temperature-transformation (T-T-T) diagram for Ti-55Ni. High-strain rate compression tests and hardness studies indicated that significant strengthening by Ti(3)Ni(4) and Ti(2)Ni(3) precipitates was accompanied by very low failure strains, i.e., low ductility. However, precipitation of TiNi(3) during high-temperature aging led to a good balance between strength (1400-2000 MPa) and ductility (10-20%).

• 出版日期2010-3-25