Microstructure and Fatigue Crack Initiation and Propagation Characteristics of Cast α+β Type Titanium Alloys Conducted with Thermochemical Heat Processing for Dental Applications
Microstructure and Fatigue Crack Initiation and Propagation Characteristics of Cast α+β Type Titanium Alloys Conducted with Thermochemical Heat Processing for Dental Applications
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牙科热化学热处理铸造α+β型钛合金的显微组织和疲劳裂纹萌生和扩展特性
DOI：
10.2320/jinstmet1952.66.11_1098
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发表时间：
2002
影响因子：
--
通讯作者：
A. Suzuki
中科院分区：
文献类型：
--
作者：
T. Akahori;M. Niinomi;K. Matsuda;A. Suzuki
采用常规热化学热处理（THP）和THP结合后热处理（THPH）对牙科用a+B型Ti-6Al-7 Nb和Ti-6Al-4V合金进行了热等静压铸造，以细化其显微组织，提高其疲劳强度而不降低其塑性。然后，本文主要研究了热等静压艾德处理后铸造Ti-6Al-7 Nb和Ti-6Al-4V合金的疲劳裂纹萌生和疲劳小裂纹扩展行为。热等静压艾德处理后的铸造Ti-6Al-7 Nb和铸造Ti-6Al-4V的疲劳极限比热等静压艾德处理后的提高了40倍左右。THP和THPH细化了组织，减小了循环应力下的有效滑移长度，使滑移均匀发生，从而显著提高了铸态Ti-6Al-7 Nb和Ti-6Al-4V的疲劳裂纹萌生和小裂纹扩展抗力。THP和THPH热等静压艾德化铸造Ti-6Al-7 Nb和Ti-6Al-4V的疲劳裂纹萌生和小裂纹扩展寿命约为总疲劳寿命的80~90倍。它们比经热等静压艾德处理的铸态Ti-6Al-7 Nb和Ti-6Al-4V增加两倍（即约40 μ m）。
AsHIP'ed cast a+b type Ti6Al7Nb and Ti6Al4V for dental applications were conducted with general thermochemical heat processing (THP) and THP combined with a post heat processing (THPH) to refine their microstructure and improved their fatigue strength without decreasing ductility. Then, the fatigue crack initiation and small fatigue crack propagation behaviors of HIP'ed cast Ti6Al7Nb and Ti6Al4V were mainly investigated in this study. Fatigue limits of HIP'ed cast Ti6Al7Nb and cast Ti6Al4V are improved about 40 by THP and THPH as compared with those of asHIP'ed ones. Fatigue crack initiation and small fatigue crack propagation resistance of HIP'ed cast Ti6Al7Nb and Ti6Al4V is improved remarkably by THP and THPH as compared with those of asHIP'ed ones because the effective slip length under the cyclic stress is decreased due to refined microstructure by THP and THPH, and the slips occur uniformly. Fatigue crack initiation and small fatigue crack propagation life of HIP'ed cast Ti6Al7Nb and Ti6Al4V conducted with THP and THPH are around 80~90 of the total fatigue life. They increase twice as much as those of asHIP'ed cast Ti6Al7Nb and Ti6Al4V (i.e. around 40).