SBIR Phase I: Rapid Superplastic Forming of Titanium Matrix Composites

* 9760593 Zimmer 这个小企业创新研究（SBIR）第一阶段将探索复合材料的超塑性成形，这通常是不可变形的。 这是一个热变形过程，需要广泛的拉伸伸长率。 与依赖于稳定的细晶粒微观结构的常规超塑性相反，复合材料中的超塑性由转化（同素异形）基质材料和稳定的非转化第二相之间的体积失配产生的内应力引起。 这种新工艺被称为相变失配超塑性（TMS），它使用热循环来获得超过200%的伸长率。用粉末冶金法制备的碳化钛（TiC）和硼化物（TiB）颗粒增强的钛金属基（MMC）复合材料由于提高了高温强度、弹性模量和耐磨性而商业化。 第一阶段将开发快速热循环方法，并测试用TiB和TiC颗粒增强的钛合金金属基复合材料的超塑性成形极限。第二阶段将为某些航空航天和商业部件开发可行的制造工艺。 商业应用将涉及通过从粉末冶金近净形中空预成型件超塑性地形成最终尺寸和形状来制造管状形状（圆形和箱形管两者）。 该技术可用于制造航空器的热气管道、汽车排气管、加强结构管、体育和娱乐用品（高尔夫球杆头、长曲棍球杆和自行车车架）、耐腐蚀/侵蚀反应容器以及造纸、化学处理和海水服务的管和配件。 ***

*** 9760593 Zimmer This Small Business Innovation Research (SBIR) Phase I will explore superplastic forming in composite materials, which are not normally deformable. It is a hot deformation process which requires extensive tensile elongations. In contrast to conventional superplasticity, which relies on a stable fine-grained microstructure, superplasticity in composites arises from internal stresses generated by the volumetric mismatch between a transforming (allotropic) matrix material and a stable, non-transforming second phase. Termed Transformation Mismatch Superplastitity (TMS), the new process uses thermal cycling to attain elongations of more than 200%. Titanium metal matrix (MMC) composites, reinforced with titanium carbide (TiC) and boride (TiB) particulate manufactured by powder metallurgy, are commercial because of improved elevated temperature strength, elastic modulus, and wear-resistance. Phase I will develop methods of rapid thermal cycling and test the superplastic forming limits of titanium-alloy MMCs reinforced with TiB and TiC particulate. Phase II would develop a viable manufacturing process for ceertain aerospace and commercial components. Commercial applications would involve fabricating tubular shapes - both circular and box tubing - by superplastically forming a final size and shape from a powder metallurgy near-net shape hollow preform. This technology could find use in manufacturing hot gas ducting for aircraft, in automotive exhaust, in stiffened structural tubing, in sporting and recreational goods (golf club heads, lacrosse sticks, and bicycle frames), in corrosion/erosion resistant reaction vessels, and in tubing and fittings for paper making, chemical processing, and seawater service. ***