(哈爾濱工業(yè)大學材料科學與工程學院， 哈爾濱 150001)
摘 要: 在77～623 K對淬火態(tài)TC4合金進行了熱循環(huán)試驗 ，測定了合金熱循環(huán)后的硬度，并與623 K時效合金的硬度進行了對比；還觀察了拉伸試樣斷口形貌。結果表明：熱應力能加速亞穩(wěn)相的分解，使合金中的位錯密度升高 ，層錯和形變孿晶的數(shù)量增多；循環(huán)溫度場作用下淬火態(tài)合金拉伸試樣斷口由韌窩型斷裂向韌窩和撕裂棱混合型斷裂轉(zhuǎn)變。
關鍵字: 鈦合金 熱循環(huán) 硬度
（School of Materials and Engineering, Harbin Institute of Technology, Harbin 150001）
Abstract:The thermal cycling tests between 77 and 623 K were performed on the as-quenched TC4 alloy, the hardness after thermal cycling were evaluated and compared with that of the alloy aged at 623K. And fractography was investigated by means of SEM. The results show that thermal stress accelerates the decomposition process of meta phase and makes an increase in dislocation density or amount of deformation twins and stacking faulty. Fractography of the quenched tensile specimen under cycling treatment changes from dimple pattern to mixed fracture with dimple and tear ridges.
Key words: titanium alloy thermal cycling hardness
