时间：2015年10月19日（星期一）上午9：00
地点：材料科学与工程学院8号楼2楼会议室

报告摘要：
       This research characterizes ferromagnetic shape memory elements for use as mechanical actuators.  A single crystal of Ni-Mn-Ga was pre-strained in compression from 0 to 6% and then the shape was recovered with a magnetic field perpendicular to the loading direction while working against a pair of springs. The magnetic field was raised from 0 to 0.64 MA/m and then reduced back to zero field.  Eight pairs of springs with combined spring constants ranging from 14.3 to 269.4 N/mm were used.  When the magnetic field was on, the sample expanded against the springs due to magnetic field induce strain (MFIS).  When the magnetic field was turned off, the springs compressed the sample back to the initial size before the next cycle.  During each cycle, force and displacement were measured and the specific work was computed. Specific work increased with the applied magnetic field and the pre-strain. The maximum specific work was 14 kJ/m3 at a pre-strain of 4.5 % strain and a magnetic field of 0.64 MA/m. For an actuator with spring-recovery, this value is five times less than values suggested in the literature which were inferred from stress-strain curves measured under various magnetic fields. The spring prescribes the load-displacement path of the magnetic shape memory (MSM) element and controls the work-output of the actuator.

附主讲人简介：
       Prof. Paul Lindquist received this Ph. D from University of Illinois, his Ph. D supervisor is C.M. Wayman, who is the most well-known scientist all round the world. Now he is the research Assistant Professor, Mater. Sci. & Eng., Boise State University, Boise, ID. He had already published 19 journal papers, and 5 patents.