(1. 江蘇大學 材料科學與工程學院，鎮(zhèn)江 212013；
2. 蘇州明志科技有限公司，蘇州 215217)
摘 要: 對不同工藝處理的鋁硅合金ZAlSi7Cu4用自約束型熱疲勞實驗機進行20↔300 ℃、20↔350 ℃和20↔400 ℃的熱循環(huán)試驗，研究不同處理工藝對該材料熱疲勞性能的影響及不同溫度幅對裂紋生長的影響。通過光學顯微鏡和掃描電鏡觀察試樣的熱疲勞裂紋形貌, 研究合金熱疲勞損傷機制。結(jié)果表明：該合金經(jīng)過T6處理后比其他兩種方式處理的合金具有更好的熱疲勞性能；顆粒的位向會影響裂紋的擴展路徑；在下限溫度不變的情況下，隨著上限溫度的提高，ZAlSi7Cu4的3種狀態(tài)合金的壽命都縮短。當下限溫度為20 ℃時，合金在上限溫度為300~350℃區(qū)間內(nèi)的溫度敏感性高于其在上限溫度為350~400℃區(qū)間內(nèi)的溫度敏感性。
關鍵字: ZAlSi7Cu4；熱疲勞；萌生；擴展；裂紋
（1. School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
2. Suzhou Ming Zhi Technology Company Limited, Suzhou 215217, China）
Abstract:The casting silumin ZAlSi7Cu4 that was treated with different technologies for heating processing was used to make a thermal cycle experiment at 20↔300 ℃, 20↔350 ℃ and 20↔400 ℃, respectively, on a self-restrict thermal fatigue experimental machine. The effect of thermal fatigue property caused by different technologies for heating processing and the effect of crack growth caused by different temperature breadths were studied. Optica1 microscopy (OM) and scanning electron microscopy (SEM) were used to examine the damage mechanisms of thermal fatigue. The results show that the sample with T6 treatment has better property than other two kinds of samples. The expansion path of crack can be influenced by the location of grains. With the increase of the maximum temperature, the lifespan of three kinds of alloys will decrease when the minimum temperature is fixed. In the interval of 300−350 ℃, the temperature sensitivity of the alloy is higher than that in the interval of 350−400 ℃ when the minimum temperature keeps at 20 ℃.
Key words: ZAlSi7Cu4; thermal fatigue; initiation; expansion; crack
