(沈陽(yáng)工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽(yáng) 110870)
摘 要: 對(duì)Al-1Si-0.3Mg和Al-7Si-0.3Mg合金在-80~20 ℃拉伸過(guò)程中的斷裂行為進(jìn)行研究。結(jié)果表明：隨著溫度的降低Al-1Si-0.3Mg合金的抗拉強(qiáng)度、屈服強(qiáng)度及伸長(zhǎng)率均呈上升趨勢(shì)；Al-7Si-0.3Mg合金的抗拉強(qiáng)度和屈服強(qiáng)度上升，伸長(zhǎng)率卻明顯下降；拉伸過(guò)程中Al-1Si-0.3Mg合金中位錯(cuò)在晶界塞積，易使相鄰晶粒內(nèi)位錯(cuò)源啟動(dòng)，使合金具有較高的塑性；Al-7Si-0.3Mg合金的位錯(cuò)在Si相邊界塞積，使相鄰晶粒內(nèi)位錯(cuò)源難以啟動(dòng)，從而造成合金具有較高的強(qiáng)度。
關(guān)鍵字: 鋁硅合金；低溫；拉伸性能；位錯(cuò)；硅相
（School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China）
Abstract:The tensile mechanical properties of Al-7Si-0.3Mg and Al-1.0Si-0.3Mg alloys at -80-20 ℃were investigated. The mechanisms of crack initiation and extension at low temperature were analyzed. The results show that the tensile strength, yield strength and ductility of Al-1.0Si-0.3Mg alloy increase with decrease of temperature. The tensile strength and yield strength of Al-7Si-0.3Mg alloy increase, but the ductility of Al-7Si-0.3Mg alloy decreases with the decrease of temperature. During the low temperature tensile process, the dislocations pile up along the boundaries of grains in Al-1.0Si-0.3Mg alloy, which make dislocation sources to trigger easily in the adjacent grains, so the ductility of Al-1.0Si-0.3Mg alloy is improved. But the dislocations pile up at the Si particles in Al-7Si-0.3Mg alloy, which prevents the dislocation sources to trigger in the adjacent grains, so, the strengths of Al-7Si-0.3Mg alloy is greater.
Key words: Al-Si alloy; low temperature; tensile property; dislocation; Si phase
