摘要
The effect of annealing temperature on the martensitic transformation of a Ti49.2Ni50.8 alloy processed by equal channel angular pressing （ECAP） was investigated by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and differential scanning calorimetry （DSC）. The as-ECAP processed and subsequently annealed Ti49.2Ni50.8 alloys consist of B2 parent phase, Ti4Ni2O phase and B19′ martensite at room temperature. Upon cooling, all samples show B2→R→B19′ two-stage transformation. Upon heating, when the annealing temperature is less than 400℃, the samples show B19′→R→B2 two-stage transformation; when the annealing temperature is higher than 500 ℃, the samples show B19′→B2 single-stage transformation. The B2-R transformation is characterized by wide interval due to the dislocations introduced during ECAP.
利用X射线衍射分析(XRD)、透射电子显微观察(TEM)与差示扫描量热分析(DSC)研究退火处理对等径角挤压Ti_(49.2)Ni_(50.8)合金马氏体相变行为的影响。经等径角挤压及后续退火处理的Ti_(49.2)Ni_(50.8)合金在室温下由B2母相、Ti_4Ni_2O相与B19′马氏体相组成。冷却过程中试样均表现出B2→R→B19′两步相变。加热过程中,退火温度不超过400°C的试样呈现B19′→R→B2两步相变;退火温度高于500°C的试样呈现B19′→B2一步相变。等径角挤压过程中引入的位错导致R相变的相变区间变宽。
基金
Project(51001035)supported by the National Natural Science Foundation of China
Project(LBH-Q14035)supported by the Postdoctoral Funds for Scientific Research Initiation of Heilongjiang Province,China
Project(HEUCF20151002)supported by the Fundamental Research Funds for the Central Universities,China
