报告题目：Inﬂuence of Foreign Object Damage on High Cycle Fatigue of Ti–6Al–4V Alloy
报告人：Prof. S.L Mannan, FNAE, FIIM, FIIW
Abstract: The inﬂuence of foreign object damage (FOD) on high cycle fatigue (HCF) of Ti–6Al–4V alloy has been investigated. FOD was induced by shooting 3.2 mm diameter steel spheres at a velocity of 300 m/s on the centre of ﬂat plate specimens using a compressed air gun facility. Both normal and 60 angular impacts were carried out. In order to assess debit in the fatigue strength due to notch effect, machined notches of the same notch proﬁle (radii and depth dimensions) as those observed in high velocity impact were also tested. The tests were conducted at room temperature and at two R ratios of 0.1 and 0.5. Fatigue life was found to be reduced in FOD impacted samples and the debit in fatigue life was much larger than that for machined notch specimens. This might be attributed to the effect of residual stresses. Further, the role of residual stresses were also brought out by comparing results of HCF tests at R = 0.1 and R = 0.5. As expected, a larger debit in fatigue life was found to occur at low R values where residual stresses were not expected to be relaxed. No signiﬁcant differences in fatigue life between the normal and angular impacted samples were noticed. Optical and SEM investigations were carried out to examine the shape of the indents and micro-structural features.
个人简介：Mannan教授是印度工程院院士（Fellowship of Indian National Academy of Engineering, FNAE）、Fellowship of Indian Institute of Metals、Fellowship of Indian Institute of Welding，曾担任印度英迪拉甘地核研究中心冶金和材料研究室（Metallurgy & Materials Group at the Indira Gandhi Centre for Atomic Research）主任，现任印度国防研究与发展组织燃气轮机研究中心（Gas Turbine Research Establishment, Defense Research and Development Organisation）顾问。他在蠕变，疲劳与断裂，高温部件寿命评估，材料加工，核与燃气轮机材料评价等方面颇有建树，已发表期刊论文275篇，并获得包括G. D. Birla Gold Medal, National Metallurgists Day Award和Materials Research Society of India Medal在内的多个奖项。