Abstract: The refractory diborides (HfB2 and ZrB2) are considered as promising ultra-high temperature ceramic (UHTCs) where low damage tolerance limits their application for the thermal protection system in re-entry vehicles. In this regard, SiC and CNT have been synergistically added as the sintering aids and toughening agents in the spark plasma sintered (SPS) HfB2-ZrB2 system. Herein, a nove...

The mechanical interaction between the surgical tools and the target soft tissue is mainly dictated by the fracture toughness of the tissue in several medical procedures, such as catheter insertion, robotic-guided needle placement, suturing, cutting or tearing, and biopsy. Despite the numerous experimental works on the fracture toughness of hard biomaterials, such as bone and dentin, only a ver...

Osteogenesis imperfecta (OI) is a genetic disease of collagen or collagen-related proteins that adversely impacts bone mass and fracture resistance. Little is known regarding the role that microdamage plays in OI and whether or not OI bone is more prone to damage accumulation than bone with unaffected collagen. The Brtl/+ mouse is a heterozygous model for OI which contains a Gly349Cys substitut...

The knowledge of the fracture of bulk metallic materials developed in the last 50 years is mostly based on materials having grain sizes, d, in the range of some micrometres up to several hundred micrometres regarding the possibilities of classical metallurgical methods. Nowadays, novel techniques provide access to much smaller grain sizes, where severe plastic deformation (SPD) is one of the mo...

It is of critical importance to improve toughness, strength, and wear-resistance together for the development of advanced structural materials. Herein, we report on the synthesis of unoxidized graphene/alumina composite materials having enhanced toughness, strength, and wear-resistance by a low-cost and environmentally benign pressure-less-sintering process. The wear resistance of the composite...

assessment of the correlation between rock brittleness and rock fracture toughness has been the subject of extensive research works in the recent years. unfortunately, the brittleness measurement methods have not yet been standardized, and rock fracture toughness cannot be estimated satisfactorily by the proposed indices. in the present study, statistical analyses are performed on some data col...

Insect cuticle is one of the most common biological materials, yet very little is known about its mechanical properties. Many parts of the insect exoskeleton, such as the jumping legs of locusts, have to withstand high and repeated loading without failure. This paper presents the first measurements of fracture toughness for insect cuticle using a standard engineering approach. Our results show ...

Effectiveness of cutting is measured by the ability to achieve a desired rate of material fracture. The work performed by a knife overcomes the material toughness to yield fracture, acts against friction between the material and the blade, and generates shape deformation. This paper studies how to control a robotic arm to achieve a desired time profile of material fracture along a prescribed cu...

The ability of bone to resist catastrophic failure is critically dependent upon the material properties of bone matrix, a composite of hydroxyapatite, collagen type I, and noncollagenous proteins. These properties include elastic modulus, hardness, and fracture toughness. Like other aspects of bone quality, matrix material properties are biologically-defined and can be disrupted in skeletal dis...

Ferroelectric ceramics are used in applications ranging from actuators and sensors to ultrasonic motors. A significant shortcoming of these materials in structural applications is their inherent brittleness. Specifically, most ferroelectrics have fracture toughness levels on the order of KIc MPa m = 1 . The characteristic of ferroelectric ceramics that makes them useful as smart materials is th...