Ti-6Al-4V热轧组织与异向性研究StructuresandAnisotropic-YOKE.PDF

Ti-6Al-4V 熱軋組織與異向性研究 Structures and Anisotropic Properties of Ti-6Al-4V Hot Rolled Plates 1* 1 1 2 2 黃仕傑 洪梓鈞 陳貞光 張孝慈 洪胤庭 1 國立台北科技大學材料科學與工程研究所 2 中國鋼鐵股份有限公司新材料研究發展處 S.J.Huang1* 1 1 2 2 , T.C.Hung , J.K.Chen , H.T.Chang , I.T.Hung 1 National Taipei University of Technology, Institute Materials Science and Engineering 2China Steel Corporation, New Materials Research and Development Department. 本研究採用Ti-6Al-4V 鍛胚 ，在三種不同溫度(950 、1100 、1200°C)下熱軋至 10 mm 厚度板材 ，依據與軋延方向呈0° 、45°以及90°等三種不同夾角的拉伸試 棒 ，分析其顯微組織與機械性質變化 ，並進行後續 850~950°C 之熱處理組織觀 察。以950°C 低溫雙相區軋延之板片 ，產生雙相等軸組織，則具備動態再結晶組 織，其RD 方向延性遠高於TD 方向延性，具備較為顯著的異向性；而在 1100°C 及 1200°C 單相區熱軋之板材 ，受軋延所拉長之β 晶粒在冷卻過程中 ，析出不同 方向之α 板片結構 ，具備相變態組織 ，延性較低、機械性質異向性較小。經熱處 理後的板片 ，主要產生α 相粗化，850°C 的熱處理使延性略為提升、強度略為降 低；900-950°C 的熱處理則因部分β 相回溶生成新的α 板片 ，延性略降、強度略 升，而對異向性之影響有限 。 Ti-6Al-4V ingots were hot-rolled at 950, 1100, and 1200°C by 82% to 10mm thickness. Tensile tests were performed along three different orientations in the hot-rolled plates: 0°, 45°, and 90° from the rolling direction to observe their difference in microstructures and properties. Heat treatments were subsequently performed at 850~950°C. The plates hot rolled at 950°C or in two-phase region formed equiaxed dual phase structures. The dual phase structure was formed by dynamically recrystallizing hot-rolled α grains to obtain deformation texture. Large difference was present in the elongation and strength of rolling and transverse directions. For plates hot rolled at 1100°C and 1200°C in β area, the elongated β grains precipitated α plates of different orientations on cooling which generated phase transformation textures. The total elongation was lower and anisotropy of mechanica