中国有色金属学报（英文版）
中國有色金屬學報（英文版）
중국유색금속학보（영문판）
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
2014年
12期
3929-3943
,共15页
Ti-6Al-4V合金%叠层制造%电子背散射衍射%原位拉伸%等离子弧焊熔敷%显微组织%塑性变形
Ti-6Al-4V閤金%疊層製造%電子揹散射衍射%原位拉伸%等離子弧銲鎔敷%顯微組織%塑性變形
Ti-6Al-4V합금%첩층제조%전자배산사연사%원위랍신%등리자호한용부%현미조직%소성변형
Ti-6Al-4V alloy%additive layer manufacturing%electron backscatter diffraction%in-situ tensile test%plasma arc welding%microstructure%plastic deformation
航天级钛合金的新型叠层制造技术(ALM)的优势体现在较低的制造成本等方面，并可替代传统加工成型工艺。由等离子弧焊熔敷叠层制造技术制备Ti?6Al?4V合金的显微组织由定向凝固生长的β柱状晶及在其晶内生长的细小的α片层组织构成。在原位拉伸过程中结合应用高速离线电子背散射衍射表征(Offline EBSD)可快速获取试样显微组织和形变特征之间的关系。揭示出不均匀变形的发生取决于柱状晶界间的应变响应。柱状滑移和基面滑移系统被激活进而导致最后出现形变滑移线，即在某些柱状晶中滑移扩展至整个晶粒；而在另一些晶粒中表现为存在应变梯度和应力集中的地方发生形变失配。形变的扩展习性受制于定向凝固生长的柱状晶生长方向及其之间的界面取向关系。在垂直于柱状晶方向的拉伸试验揭示存在剧烈的变形局域化。基于原位拉伸观测及高速的离线电子背散射衍射表征结果，本文作者提出从微观到宏观形变扩展的控制机制。
航天級鈦閤金的新型疊層製造技術(ALM)的優勢體現在較低的製造成本等方麵，併可替代傳統加工成型工藝。由等離子弧銲鎔敷疊層製造技術製備Ti?6Al?4V閤金的顯微組織由定嚮凝固生長的β柱狀晶及在其晶內生長的細小的α片層組織構成。在原位拉伸過程中結閤應用高速離線電子揹散射衍射錶徵(Offline EBSD)可快速穫取試樣顯微組織和形變特徵之間的關繫。揭示齣不均勻變形的髮生取決于柱狀晶界間的應變響應。柱狀滑移和基麵滑移繫統被激活進而導緻最後齣現形變滑移線，即在某些柱狀晶中滑移擴展至整箇晶粒；而在另一些晶粒中錶現為存在應變梯度和應力集中的地方髮生形變失配。形變的擴展習性受製于定嚮凝固生長的柱狀晶生長方嚮及其之間的界麵取嚮關繫。在垂直于柱狀晶方嚮的拉伸試驗揭示存在劇烈的變形跼域化。基于原位拉伸觀測及高速的離線電子揹散射衍射錶徵結果，本文作者提齣從微觀到宏觀形變擴展的控製機製。
항천급태합금적신형첩층제조기술(ALM)적우세체현재교저적제조성본등방면，병가체대전통가공성형공예。유등리자호한용부첩층제조기술제비Ti?6Al?4V합금적현미조직유정향응고생장적β주상정급재기정내생장적세소적α편층조직구성。재원위랍신과정중결합응용고속리선전자배산사연사표정(Offline EBSD)가쾌속획취시양현미조직화형변특정지간적관계。게시출불균균변형적발생취결우주상정계간적응변향응。주상활이화기면활이계통피격활진이도치최후출현형변활이선，즉재모사주상정중활이확전지정개정립；이재령일사정립중표현위존재응변제도화응력집중적지방발생형변실배。형변적확전습성수제우정향응고생장적주상정생장방향급기지간적계면취향관계。재수직우주상정방향적랍신시험게시존재극렬적변형국역화。기우원위랍신관측급고속적리선전자배산사연사표정결과，본문작자제출종미관도굉관형변확전적공제궤제。
Additive layer manufacturing (ALM) of aerospace grade titanium components shows great promise in supplying a cost-effective alternative to the conventional production routes. Complex microstructures comprised of columnar remnants of directionally solidifiedβ-grains, with interior inhabited by colonies of finerα-plate structures, were found in samples produced by layered plasma welding of Ti?6Al?4V alloy. The application of in-situ tensile tests combined with rapid offline electron backscatter diffraction (EBSD) analysis provides a powerful tool for understanding and drawing qualitative correlations between microstructural features and deformation characteristics. Non-uniform deformation occurs due to a strong variation in strain response between colonies and across columnar grain boundaries. Prismatic and basal slip systems are active, with the prismatic systems contributing to the most severe deformation through coarse and widely spaced slip lines. Certain colonies behave as microstructural units, with easy slip transmission across the entire colony. Other regions exhibit significant deformation mismatch, with local build-up of strain gradients and stress concentration. The segmentation occurs due to the growth morphology and variant constraints imposed by the columnar solidification structures through orientation relationships, interface alignment and preferred growth directions. Tensile tests perpendicular to columnar structures reveal deformation localization at columnar grain boundaries. In this work connections are made between the theoretical macro- and microstructural growth mechanisms and the observed microstructure of the Ti?6Al?4V alloy, which in turn is linked to observations during in-situ tensile tests.
