擠壓強(qiáng)化對(duì)TC17鈦合金孔結(jié)構(gòu)疲勞壽命的影響

擠壓強(qiáng)化對(duì)TC17鈦合金孔結(jié)構(gòu)疲勞壽命的影響Effect of Cold Expansion on Fatigue Life of Hole Structure of TC17 Titanium Alloy

為提高TC17中心孔試樣的疲勞性能，采用掃描電鏡、粗糙度儀、X射線衍射儀等對(duì)孔壁表面完整性進(jìn)行分析，研究孔擠壓強(qiáng)化工藝對(duì)試樣疲勞性能的影響。結(jié)果表明：過(guò)盈量為0.18 mm的孔擠壓試樣最小疲勞壽命（14718次）高于原始試樣的最大疲勞壽命（13965次）；同過(guò)盈量為0.28 mm和0.38 mm的試樣相比，其疲勞壽命分散性較小、無(wú)明顯的應(yīng)力集中現(xiàn)象，具有良好的疲勞壽命增益效果；孔壁表面粗糙度值最低；孔壁內(nèi)側(cè)形成一定深度的強(qiáng)化層；孔邊產(chǎn)生的殘余壓應(yīng)力場(chǎng)有效地抑制了孔壁內(nèi)表面疲勞裂紋的產(chǎn)生，有利于提高孔結(jié)構(gòu)的疲勞性能。

In order to improve the fatigue performance of TC17 central hole specimen, the hole wall surface integrity was characterized by scanning electron microscopy (SEM), roughness meter, X-ray diffraction, and the influence of hole cold expansion(HCE) parameter on the fatigue performance of the hole specimens was investigated. The results show that the minimum fatigue life (14718 cycle) of the HCE specimens with an expansion value of 0.18 mm is higher than the original specimen (13965 cycle). Compared to the specimens with the expansion values of 0.28 mm and 0.38 mm, the fatigue life dispersion is less, no obvious stress concentration phenomenon is found, and it has the best fatigue performance than the other two. The surface roughness value of hole wall is the lowest after the HCE with 0.18 mm, the inner hole wall forms a certain depth of strengthened layer, the residual compressive stress produced in the hole side effectively suppresses the produce of fatigue cracks in the inner hole wall, so the fatigue performance of hole structure is improved.

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