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采用透射电子显微镜研究Ti49.2Ni50.8合金中Ti3Ni4析出相在等径角挤压及中间退火过程中的演化规律.固溶态Ti49.2Ni50.8合金在450℃时效处理10～60 min以获得尺寸为37～75 nm的Ti3Ni4析出相.在450℃等径角挤压处理1道次后,时效处理10 min和30 min试样中Ti3Ni4析出相完全溶解;而在时效处理60 min试样中Ti3Ni4析出相尺寸减小.Ti3Ni4析出相完全溶解的临界尺寸范围为37～68 nm.等径角挤压态试样的位错密度取决于Ti3Ni4析出相的初始尺寸.随初始时效时间从10 min延长至60 min,试样的位错密度先增加然后降低.“,”The evolution of Ti3Ni4 precipitates in Ti49.2Ni50.8 alloy during equal channel angular pressing (ECAP) and intermediate annealing was investigated by transmission electron microscopy. The solution-treated Ti49.2Ni50.8 alloy was aged at 450 ℃ for 10 to 60 min to obtain Ti3Ni4 precipitates ranging from 37 to 75 nm. After ECAP at 450 ℃ for one pass, Ti3Ni4 precipitates introduced by aging for 10 and 30 min totally dissolve into the matrix; however, those produced by aging for 60 min become smaller. The critical size of Ti3Ni4 precipitates to totally dissolve into matrix is determined to be in the range of 37-68 nm. The dislocation density of ECAP-processed samples depends on the initial size of Ti3Ni4 precipitates after aging. With increasing the duration of initial aging from 10 to 60 min, the dislocation density firstly increases and then decreases.