基于Prasad判据的全片层TA15钛合金塑性流动失稳预测  

Prediction of Plastic Flow Instability of TA15 Titanium Alloy with Full Lamellar Based on Prasad Criterion

作　　者：董显娟[1,2] 鲁世强[2] 王克鲁[2] 郑海忠[2] 肖璇[2] 

机构地区：[1]南京航空航天大学材料科学与技术学院,南京210016 [2]南昌航空大学材料科学与工程学院,南昌330063

出　　处：《航空材料学报》2010年第2期11-16,共6页Journal of Aeronautical Materials

基　　金：江西省自然科学基金(2008GZC0041);江西省教育厅科技项目(GJJ08203)

摘　　要：对全片层TA15钛合金进行等温恒应变速率压缩试验,采用Prasad失稳判据预测合金在750～1100℃,0.001～10s-1热力参数范围内的塑性流动失稳,并对变形后试样进行宏观和微观观察。结果表明,全片层TA15钛合金在试验参数范围内热变形时存在较大区域的流动失稳,且随着变形温度的降低,失稳区范围有从高应变速率向低应变速率逐渐扩展的趋势。在(α+β)两相区变形,失稳缺陷主要有宏观剪切裂纹、原始β晶界裂纹和局部流动三种形式。在β单相变形,失稳主要是原始β晶粒沿着垂直于压缩轴线方向拉长,且在部分晶界附近分布着变形带。Isothermal constant strain rate compression tests of TA15 alloy with full lamellar have been carried out. The plastic flow instability was predicted in the temperature range 750~1100℃ and strain rate range 0.001~10s-1. The corresponding macro and microstructures of deformed specimens were observed. The results show that the instability criterion predicts a large region of flow instability,which extends to low strain rate region with decreasing deformation temperature. The specimens deformed in （α＋β） phase field demonstrates three kinds of flow instabilities,namely macro shear cracks,prior β boundary cracks and flow localization. The flow instability in β phase field is characterized by the elongated prior β grains perpendicular to compression axial and deformation bands distributed in prior β boundaries.

关 键 词：TA15钛合金 Prasad判据 流动失稳 原始β晶界裂纹 

分 类 号：TG146.2[一般工业技术—材料科学与工程]