热变形温度对TC18钛合金显微组织和力学性能的影响  

Influence of hot deformation temperature on microstructure and mechanical properties of TC18 alloy

作　　者：沙爱学[1] 李兴无[1] 王庆如[1] 鲍如强[1] 

机构地区：[1]北京航空材料研究院,北京100095

出　　处：《中国有色金属学报》2005年第8期1167-1172,共6页The Chinese Journal of Nonferrous Metals

摘　　要：研究了热变形温度从(tβ-25℃)^(tβ+20℃)变化时,对TC18钛合金模锻件显微组织和拉伸、冲击、断裂韧度等主要力学性能的影响。结果表明:合金强度随变形温度升高变化不大,均在1200MPa左右;而塑性、冲击韧性以及断裂韧度等性能指标对热变形温度变化反应敏感;两相区变形时获得双态组织,合金的塑性和冲击韧性较高,Ψ≥40%,aKU≥40J/cm2;但断裂韧度偏低,KIC<50MPa.m1/2。β区变形时获得片状组织,合金具有较高的断裂韧度,KIC>50MPa.m1/2;但塑性和冲击韧性较低,Ψ≥20%,aKU≥25J/cm2。在相变点附近变形时容易导致合金组织和性能出现不均匀性。The influence of die forging temperature （changing from （tβ-25℃）～（tβ＋20℃） on microstructure and mechanical properties such as tensile, impact and fracture toughness are studied when the other parameters kept consistent. The results show that ultimate strength of TC18（Ti-5Al-5Mo-5V-1Cr-1Fe） alloy remains at about 1200 MPa when the die forging temperature increases. The ductility, impact property and fracture toughness are sensitive with the variety of die forging temperature. When deforming in α-β field, bimodel structure can be obtained. Ductility and impact toughness of the alloy are relatively high, but the fracture toughness is relatively low. Under this condition, the value of reduction of area and αKu are over 40% and 40 J/cm^2 , respectively; KIC is lower than 50 MPa·m^1/2. When deforming in β field, lamellar structure can be obtained. The fracture toughness is relatively high, but ductility and impact toughness are lower than α-β field deforming. Under this condition, KIC is over 50 MPa·m^1/2 , the value of reduction of area and αKU are over 20% and 25 J/cm^2 , respectively. When deforming near beta transition point, it may lead to the uncertainty of microstructure and properties of TC18 alloy.

关 键 词：TC18钛合金 热变形温度 显微组织 力学性能 

分 类 号：TG146.23[一般工业技术—材料科学与工程]