Ji Yuanchao, Wang Dong, Ding Xiangdong, Otsuka Kazuhiro, Ren Xiaobing
Frontier Institute of Science and Technology and State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Ferroic Physics Group, National Institute for Materials Science, Tsukuba, 305-0047 Ibaraki, Japan.
Phys Rev Lett. 2015 Feb 6;114(5):055701. doi: 10.1103/PhysRevLett.114.055701. Epub 2015 Feb 2.
We report that R martensite isothermally forms with time in a solution-treated Ti(48.7)Ni(51.3) single crystal. This abnormal formation originates from the growth of a short-range ordered R phase with time, i.e., the "crystallization" of strain glass. The established time-composition-temperature Ti-Ni diagram shows a time evolution of the R phase and composition-temperature phase diagram. The presence or absence of the R phase in this new diagram, as well as in other conditions (like doping Fe or aging), is explained in a unified framework of free-energy landscape. Our finding suggests a new mechanism for the isothermal martensite formation, which could be applied to other metal and ceramic martensitic systems to find new phases and novel properties.
我们报道了在固溶处理的Ti(48.7)Ni(51.3)单晶中，R马氏体随时间等温形成。这种异常形成源于短程有序R相随时间的生长，即应变玻璃的“结晶”。建立的时间-成分-温度Ti-Ni相图显示了R相的时间演化以及成分-温度相图。在这个新相图以及其他条件（如掺杂Fe或时效）下R相的存在与否，在自由能景观的统一框架中得到了解释。我们的发现提出了一种等温马氏体形成的新机制，该机制可应用于其他金属和陶瓷马氏体系统以发现新相和新特性。
