Influence of the Ageing Temperature on the Selected Mechanical Properties of the Ti6Al7Nb Alloy
Influence of the Ageing Temperature on the Selected Mechanical Properties of the Ti6Al7Nb Alloy
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时效温度对Ti6Al7Nb合金力学性能选择的影响
DOI：
10.4028/www.scientific.net/kem.641.120
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
E. Rożniata
中科院分区：
文献类型：
--
作者：
R. Dabrowski;J. Krawczyk;E. Rożniata
本文介绍了时效温度对两相Ti6Al7Nb合金的硬度、断裂韧性(用线弹性断裂力学-KIC试验检验)和冲击强度(KV)等力学性能影响的研究结果。在时效温度范围内进行了研究：从所选择的加热温度(两相范围)开始，合金先前的过冷温度为450×650℃-等于970C。加热温度是根据合金在ΔL=f(T)系统中加热的膨胀曲线确定的，其中：ΔL-样品长度T的变化，然后在系统中进行微分：ΔL/ΔT=f(T)。试验中使用的是LINSEIS公司的L78 R.I.T.A膨胀仪。利用卡尔·蔡司公司的Axiovert 200MAT光学显微镜对合金在450×650°C时效温度范围内的显微组织进行了研究。结果表明，在体积分数为APP的显微组织中，初生α相存在近等轴晶。30%)，由过饱和α相形成的新片层β相的体积分数增加。在上述温度范围内，随着时效温度的升高，合金的硬度从305增加到324HV，应力强度因子KIc从67.3下降到48.6 Mpa/2，冲击强度(KV)从40.2下降到31.3 J。结果表明，冲击试验样品的断口特征与时效温度和材料硬度没有本质区别。用扫描电子显微镜NovaNanoSEM450进行了断口分析。
The results of investigations of the influence of the ageing temperature on the selected mechanical properties i.e. hardness, fracture toughness (examined by the linear elastic fracture mechanics - KIc test) and impact strength (KV) of two-phase Ti6Al7Nb alloy, are presented in the hereby paper. Investigations were performed in the ageing temperatures range: 450÷650°C of the alloy previously undercooled from the selected heating temperature (in two-phase range) - equal 970°C. The heating temperature was determined on the basis of the dilatometric curve of the alloy heating in the system ΔL = f ((T), where: ΔL – change of the sample length, T – temperature, which was then differentiated in the system: ΔL/ΔT = f (T). The dilatometer L78 R.I.T.A of the LINSEIS Company was used in the tests. Investigations of the alloy microstructure in the ageing temperatures range 450÷650°C were carried out by means of the light microscope Axiovert 200 MAT of the Carl Zeiss Company. It was found that nearly equiaxial grains of the primary α phase occur in the microstructure (of the volume fraction app. 30%) and that the volume fraction of the new lamellar α phase - formed from the supersaturated β phase - increases. With an increase of the alloy ageing temperature, in the mentioned above range, a small increase of its hardness from 305 to 324HV as well as a decrease of stress intensity factor KIc from 67.3 to 48.6 MPa x m1/2 and impact strength (KV) from 40.2 to 31.3 J. The impact tests results were supplemented by the fractographic documentation. It was found, that the characteristic features of the fractures of impact test samples do not exhibit essential differences in dependence of the ageing temperature and material hardness. The fractographic investigations were performed by means of the scanning electron microscope NovaNanoSEM 450.