Cyclic Deformation and Damage Mechanisms in additive manufactured Ti-6Al-4V with Graded Microstructures

增材制造（AM），也称为3D打印，与传统制造工艺相比，已被广泛认为能够提供一系列物流，经济和技术优势。例如，增材制造为航空航天领域开辟了新的商机，因为它缩短了上市时间，提高了购买-飞行比率，特别是钛合金。然而，工业上广泛采用增材制造来生产金属工程零件/部件仍然是一个挑战。对AM制造材料的可靠性缺乏了解以及对工程结构完整性的相关担忧已被确定为成功商业化这一有前途的制造工艺的障碍之一。Ti-6Al-4V是最流行的钛合金，广泛用于航空航天应用。位于德比的罗尔斯·罗伊斯公司已将AM技术应用于航空发动机BLISKS（叶片式发动机）的维修，美国的GE航空公司已为LEAP航空发动机开发了AM制造的燃油喷嘴。随着增材制造进入更重负载的最终用途部件的生产，特别是在航空航天领域，提高对增材制造零件/部件在循环（疲劳）负载下的机械行为的理解至关重要。这就需要为包含AM制造零部件的安全关键工程系统开发基于机械的寿命评估程序。通过积极与英国世界知名的AM制造技术中心（MTC）和最终用户合作，（Rolls-Royce PLC），该项目将开发一种经过实验验证的微观结构-在对AM构建的Ti-6Al-4V进行疲劳裂纹萌生寿命预测时，可采用基于的模型。

Additive manufacturing (AM), also called 3D printing, has been widely recognised to be capable of offering a range of logistical, economic and technical advantages when compared with conventional manufacturing processes. For example, AM has opened up new business opportunities for the aerospace sector because of its reduced time-to-market and higher buy-to-fly ratio, in particular for titanium alloys. However, the widespread adoption of AM by industries for the production of metallic engineering parts/components remains a challenge. Lack of knowledge about the reliability of AM-built materials and associated concerns about engineering structural integrity has been identified as one of the hurdles to successfully commercialise this promising manufacturing process.Ti-6Al-4V is the most prevalent titanium alloy and is widely used in aerospace applications. Rolls-Royce PLC at Derby has applied AM technologies to repair aero-engine BLISKS (Bladed-Disks) and GE Aviation in the USA has developed AM-built fuel nozzles for the LEAP aero-engines. With AM moving into the production of more heavily loaded end-use components, particularly within the aerospace sector, improved understanding of the mechanical behaviour of AM parts/components under cyclic (fatigue) loading is essential. This requires the development of a mechanistic based lifetime assessment procedure for safety-critical engineering systems that contain AM-built parts/components.By engaging actively with both the UK's world-renowned AM manufacturing technology centre (MTC) and an end-user (Rolls-Royce PLC), this project will develop an experimentally-validated microstructure-based model that can be adopted when undertaking a lifetime prediction against fatigue crack initiation in AM-built Ti-6Al-4V.